# Experimental passive solar wood kilns



## Poindexter (Nov 17, 2015)

I am going for it.  Have to start putting up wood for winter of 16-17 now so I can have everything C/S/S by March of 2016.

No more pallets.  No more fungus.  No more 18-22% MC.

I am going to build hoop style greenhouses, 42x96 inches.  Same footprint as 2 common pallets.  

2 squares under each iteration represent 6 cinderblocks under each segment, same as I have been running under my broken pallets successfully.

Floor on each will be ground contact rated pressure treated 2x4 with a layer of vapor barrier plastic and then a floor of common CDX plywood.

Verticals, common 2x4 stud wall.

The arc drawn on each represents the plastic roofing sheet, with no roof framing shown.  One key is the gap at the bottom to let condensate drip outside the kiln.

Roof framing will be 3/4" PVC pipe on 24" centers.  

Hope to begin construction of the first module Saturday.  I am going to have green splits delivered this year so I can just build modules and stack delivered splits.







Discussion welcome.


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## Poindexter (Nov 17, 2015)

Passive solar.  I forgot to include "passive" in the title.  Sorry.


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## ElmBurner (Nov 17, 2015)

What moisture content are you shooting for, if 18-22% won't cut it?


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## Poindexter (Nov 17, 2015)

I would like to see 12 to 16 (wet basis) as shown on a consumer grade meter with a battery and two metal pins.


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## Frank625 (Nov 17, 2015)

Here you go how about 11% on a fresh red oak split


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## Jags (Nov 17, 2015)

Poindexter said:


> Passive solar.  I forgot to include "passive" in the title.  Sorry.


Fixed it for you.


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## iluvjazznjava (Nov 17, 2015)

I'm interested in your project, as I am considering a budget solar kiln a project to tackle in my near future.  If I understand your drawings correctly, you are shooting for something 42" wide and then 96" tall?  That seems quite narrow to me, but maybe you aren't trying to build a kiln you can really move around in - more of a stand outside and load it up type of concept.  You probably want to give yourself a few extra inches on each dimension for a bit of leeway.  I've heard of using PVC pipe for this sort of thing, but in my somewhat limited experience with it, it was semi-flexible, but not super flexible.  I'm curious to see if you can get the flex you need to build somewhat narrow and tall, rather than vice-versa.  Most of the plans I have seen for similar structures call for them to be about as wide as they are tall.  

Have you considered how you are going to vent it?  I seem to recall another thread where the builder used a simple box fan on one end with an opening on the other which seemed to work.  

Good luck and keep us updated on your progress!


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## iluvjazznjava (Nov 17, 2015)

So looking again at your description ... I assume by "passive" you mean no sort of mechanical ventilation?  I can't quite envision how your condensate removal actually functions.  Is the idea that the condensation on the inside of the plastic will run down and drain at the bottom on the sides?  If so, my experience with greenhouses tells me that may not work, since condensate on the inside of the roof (if vents weren't used) just tended to drip right back down when things cooled off at night.

I hope it works though - would probably keep things simpler.


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## DougA (Nov 17, 2015)

I think you are going to need a vent or fan along the top. It could be at the ends but a kiln works by eliminating the condensation and I agree with iluvjazz that the condensate will simply drip back down.  The easiest would be to get a solar powered roof vent and put it at the top or put a roof vent strip like you see on roof peaks (8' long).


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## Poindexter (Nov 17, 2015)

Sorry fellas, I was hurrying.  42x96" floor, then vertical framing 7-8 feet tall.  

If I can fit two layers of 16" splits on the floor in side by stacks 7 feet tall and 8 feet long I'll have 1.2 green cords of wood in each module that after thorough seasoning (18% shrinkage for me) should come right in at one seasoned cord per module.  

Load from the lawn, not walk around inside of kiln yes.

Thanks Jags.

Frank625 wasn't that wood stacked four years?  I think I remember your thread.  I don't have enough land to wait that long.  What I have split and stacked in March is what I have to burn in September.

jazznlava, I built a hoop style greenhouse for my wife to garden in a couple or three years ago.  I am probably not communicating my design clearly, but bending 3/4 white PVC pipe to my needs will/should work for what I mean even it is doesn't work for what I said.

I have a couple ideas about condensation, but I won't have any liquid water to observe for several months yet.  For now I need to get my floors built and my cordwood stacked.  I figure I'll tarp the green stuff as I go to keep the worst of the snow off it; then pipe and plastic cover in maybe early march or so.


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## Andy S. (Nov 17, 2015)

Poindexter said:


> I am going for it.


Good luck with it and good call. I ran a small-scale experiment this year and it was a success. Hope the same is true for you. Please post pics of your finished product.


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## iluvjazznjava (Nov 17, 2015)

Yes, please post pics of your progress and finished project.  It sounds promising - I just can't quite visualize it.


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## paul bunion (Nov 17, 2015)

Poindexter said:


> I would like to see 12 to 16 (wet basis) as shown on a consumer grade meter with a battery and two metal pins.



I thought that consumer grade moisture meters were all displaying moisture on a dry basis.  Dry basis being the weight of the water/weight of the wood when bone dry.   Am I mistaken?


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## iluvjazznjava (Nov 17, 2015)

paul bunion said:


> I thought that consumer grade moisture meters were all displaying moisture on a dry basis.  Dry basis being the weight of the water/weight of the wood when bone dry.   Am I mistaken?


That is my understanding as well - the meter is showing the moisture content of the wood (not the "dry" content).


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## Poindexter (Nov 17, 2015)

iluvjazznjava said:


> Have you considered how you are going to vent it?



Can I get back to you on this?  I agree that it is a key point, I have considered it, I am going to try several things and it might be a lot easier with pictures and brief captions rather than pages of text.



iluvjazznjava said:


> I seem to recall another thread where the builder used a simple box fan on one end with an opening on the other which seemed to work.



I am absolutely stepping forward from the work done by Solarguy2003 in this thread: https://www.hearth.com/talk/threads...to-store-and-dry-wood-working-awesome.129149/ 

The one thing he did that really got my attention was the vapor barrier in the floor between ground water and his woodpile.  I guess it isn't necessary in some areas, but I got to do this.  

A few years ago I had about a cord at 18% per handheld meter, it was my best cord.  I moved it to right by the man door to the garage, put it on pallets on the ground, then covered top and all sides with plastic.  Within a week of good sunshine with nightly freezes and daily thaws it was up to 25% per handheld meter, I checked again because it wasn't burning as good as it had before.

Frank625 has a shed that belongs in the Taj Mahal section  of the "show us your wood shed" sticky at the top of this page.  I just don't have room to wait that long.  https://www.hearth.com/talk/threads/opening-up-the-wood-shed-after-4-years.148952/


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## Poindexter (Nov 17, 2015)

I _think_ (and I stand to be corrected) the hand held meters under $100 read the resistance between the two pins - the water and the wood together- and express the result in wet basis.  I googled this a little bit, begreen probably knows for sure and has maybe links to back it up.

At the end of the summer, I want to see 12-16% on my handheld $35 meter.


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## DougA (Nov 17, 2015)

Poindexter said:


> I want to see 12-16% on my handheld $35 meter.


That's very low. 

I was looking at building a solar kiln for a lot of oak, cherry & walnut planks I had cut at a sawmill.  The one that appeared to most simple was the Oregon one. http://owic.oregonstate.edu/solarkiln/plans.htm If you have some spare windows, plywood and tarpaper, it's not that difficult. Not sure if you get enough sun in the winter to have a kiln work well.
In the end, I decided that I don't have an area that gets good sun that I want to build one on, so I stacked the wood separated by stickers in the south facing garage. In this case, slow drying over the winter and into next summer is better for the boards than fast drying in a kiln. Not the same as your firewood though.


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## Poindexter (Nov 18, 2015)

DougA said:


> That's very low.  I was looking at building a solar kiln for a lot of oak, cherry & walnut planks... slow drying over the winter and into next summer is better for the boards than fast drying in a kiln. Not the same as your firewood though.



Good points.  I seem to be out on my own here with what I am trying to do.  I will be experimenting with ventilation strategies.  I am concerned about pulling out too much moisture too fast to end up with case hardened splits that are dry on the outside and a bunch of water trapped within.  

But I got all summer.  I am reading up on case hardening as a negative outcome of the kiln drying process now.


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## Knots (Nov 18, 2015)

DougA said:


> I think you are going to need a vent or fan along the top. It could be at the ends but a kiln works by eliminating the condensation and I agree with iluvjazz that the condensate will simply drip back down.  The easiest would be to get a solar powered roof vent and put it at the top or put a roof vent strip like you see on roof peaks (8' long).


This.  My last house came with a green house that I used for wood storage.  It did not have good venting.  It was much better than outdoor storage, but for the most part the sun would extract the moisture from the wood during the day, and then when the glass cooled at night the moisture would condense and it would "rain" inside.


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## MikeK (Nov 18, 2015)

Poindexter said:


> I _think_ (and I stand to be corrected) the hand held meters under $100 read the resistance between the two pins - the water and the wood together- and express the result in wet basis.  I googled this a little bit, begreen probably knows for sure and has maybe links to back it up.
> 
> At the end of the summer, I want to see 12-16% on my handheld $35 meter.



I just bookmarked this link for my own use, according to which it appears our meters are dry basis, I had no idea before reading.  

https://www.hearth.com/talk/wiki/determine-moisture-content-of-wood/

I am super excited to see pics and read about your results!


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## solarguy2003 (Nov 18, 2015)

Go for it!

I'm sure you have 7 ideas for how to vent each enclosure.  The first thing that pops in my head is 4" aluminum duct, like for dryers.  A 5' piece is 6 bucks at menards.  Cut it up into 4 or 5 pieces.  Pop rivet or screw a sheet metal plate over the end at a 45* angle or so to keep most of the rain out.  A slightly more expensive option is to stick an elbow on the top so the prevailing winds can't shove rain in there sideways.

I'm still tickled pink with the solar greenhouse.

I explored the option of a solar fan, and I was totally underwhelmed by the bang/buck ratio.  I love solar, but not if it's stupidly expensive...

Any vented, plastic covered stack that stops moisture migration up from the ground, keeps all the rain and snow off, and has some solar heat, is going to work well.  Exactly how fast, and how well, I look forward to your data.  

solarguy


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## Poindexter (Nov 18, 2015)

Been reading up on case hardening specifically and drying effects in general.

US Forestry Service _Dry Kiln Operator's Manual_ index here:

http://www.fpl.fs.fed.us/products/p...opic.php?groupings_id=113&sort_criteria=title 

Chapter One: http://www.fpl.fs.fed.us/documnts/usda/ah188/chapter01.pdf 
Chapter Eight: http://www.fpl.fs.fed.us/documnts/usda/ah188/chapter08.pdf 
Chapter Nine: http://www.fpl.fs.fed.us/documnts/usda/ah188/chapter09.pdf 

The short version seems to be to avoid case hardening (moisture trapped inside each split) I need to dry my stacks gently down to and just below the Fiber Saturation Point (FSP) before I really crank up the heat to force the last of the water out.  This I can do.

There is a really interesting section in the wikipedia article about kiln drying that uses red oak as a specific example.  I can't get any red oak here, but if you can get to a good quantity of it and know the Greek alphabet: https://en.wikipedia.org/wiki/Wood_drying#Model might be an interesting read.


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## edge-of-the-woods (Nov 18, 2015)

Is that hooped-over 3/4" PVC going to be able to stand up under the weight of any snow you're going to get over it?  Or are you moving it someplace else during snowfall season?


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## DougA (Nov 18, 2015)

Poindexter said:


> might be an interesting read.


I clicked the link, my eyes went blurry, my brain went fuzzy and I remembered how much I hated that stuff in high school. Now I need a drink.


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## kversch (Nov 29, 2015)

I'll be watching to see how this works out.   Keep us up to date


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## DoubleB (Nov 30, 2015)

Poindexter said:


> The short version seems to be to avoid case hardening (moisture trapped inside each split) I need to dry my stacks gently down to and just below the Fiber Saturation Point (FSP) before I really crank up the heat to force the last of the water out.



Why are you worried about case hardening?  Case hardening is bad for lumber (stresses and internal cracks), but I don't know why that's a problem with firewood.  I say let 'er rip as fast as you can with firewood.

You really don't want to hold yourself to lumber standards because then you also need to worry out about end checking, which has afflicted nearly every piece of dry firewood any of us has ever burned.


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## BlueRidgeMark (Nov 30, 2015)

Poindexter said:


> I am concerned about pulling out too much moisture too fast to end up with case hardened splits that are dry on the outside and a bunch of water trapped within.




Hasn't been a problem with any solar kiln I've ever read about.   Never even read about any body worrying about it until this thread.

I think the solar powered fan is your best bet for ventilation.  Free energy, no digging trenches to run electricity, and it turns itself off at night when you don't want it running and pulling in damp air.


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## Poindexter (Dec 1, 2015)

So two comments about case hardening same day, I'll step up to those here directly. 

Construction is on hold for now because my charity cord is homeless.  Every year I stack one cord of the 8-10 that I process to give away.  You would think giving away a cord of seasoned wood in Alaska in December would be easy.  Usually the men's group from my church is here within a week when I tell them the cord is ready, with a big trailer and a bunch of guys and away it goes.  It is still here this year and it is in the way of my new construction project.  I guess everyone has enough wood this year ;-)  In the fullness of time, in the fullness of time.

In the meantime, case hardening.

When I open an air dried piece of primo seasoned birch, I expect to find about 16% MC down close to the bark half way between the ends of the split.  Smack in the middle of a freshly split face, maybe 14ish %, and around the edges of the freshly split face, 12%.  

Like in this picture:








So lets back up and think about case hardening.  In our lifetimes, 1900 to present, the most common place to see the words "case hardened" was on a padlock.  Like on our lockers in high school.  What the lock makers were doing was building the locks out of relatively inexpensive steel, and then case hardening the surface of the lock.  It is a relatively simple, repeatable heat treatment that makes the surface of the metal bar, or the lock shackle much harder than the original steel was.

Pre 1900 case hardening was used to strengthen firearms.  Even in the mid 1700s the lock parts of a flintlock would be case hardened before final assembly so the rubbing surfaces wouldn't wear each other out as quickly.  Hard on hard instead of soft on soft.  On civil war era revolvers, case hardening is the process (using bone chunks and charcoal in a small furnaces) that causes the mottled colors on the receivers.

Case hardened wood is the same concept - a heat treatment that hardens the surface - but the end result is water (potentially a lot of it) trapped inside a board that feels dry on the outside.  As above.

It sounds to me like FionaD got into some case hardened cord wood splits in this thread, https://www.hearth.com/talk/threads/seriously-thinking-about-giving-up-on-burning-wood.149234/ , specifically:



			
				FionaD said:
			
		

> I've measured some 'kiln dried' splits up to 45% at their core!



In general, any split that explodes like popcorn inside my stove when water trapped inside flashes to steam is a bad thing.  Likewise, any water trapped inside above the fiber saturation point is a bad thing.  

Using the general variables L sub r, L sub t and L sub l to represent the movement of water radially, tangentially and lengthwise, the quickest way to get to fiber saturation point is to maximize L sub l, lengthwise motion of liquid water through the existing tubules via capillary action.  Once the tubules (vertical in tree and lengthwise in the split) are empty, all further drying is by diffusion and the lengthwise water loss is no longer 10x the radial and tangential - because it is all diffusion now.  The cellulose fiber is all still saturated with water, but the tubules are empty.  It's the capillary action that makes L sub l so fast.  

So once I get to FSP in my kiln all further drying will be by diffusion, capillary action is done and case hardening is no longer a significant concern.  That is to say once capillary movement is done, it doesn't matter how small the tubules shrink at the ends of the splits in a hot kiln because all further drying is via diffusion anyway.

Cranking the kiln up and shrinking the ends of the tubules before capillary action is finished is where the risk of popcorn splits arises.


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## renewablejohn (Dec 1, 2015)

Come on I have been commercially solar kiln drying logs for over 5 years and have never had any examples of case hardened logs. Where on earth are you drying these logs if you think you can get them case hardened in the sahara desert.


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## DoubleB (Dec 1, 2015)

Poindexter, 

As far as I know, case hardening metal items (for example, gears) changes the metallurgy to increase strength.  However, I have never heard that causing stress in the outer layer of wood changes the ability of the wood to diffuse water.

In a former life I operated an R&D lumber dry kiln and developed the drying schedules.  I never read or observed that case hardening slowed down drying.  I never saw "If you dry lumber too quickly it might take too long and cause case hardening."  Rather, it was "If you dry too quickly it might cause case hardening."  

I'm always learning something new so maybe I'm wrong, but you can give it a shot and compare both ways and tell us what you find.  (I didn't have time to read FionaD's whole thread).

By the way, kudos for giving away a cord of wood each year.  Merry Christmas!


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## Poindexter (Dec 11, 2015)

Making some progress.  

Finally got the corner of my L shaped wood pile cleared out, all the rest justifies to the one corner.






And I took five pallets to the dump.  That was a GREAT feeling.






Now the real work begins.  I am not going to do this every year (thank God), but it is worth it to me to do it once and get it done.  The pictured cinderblock needs to drop 1/4" to be within half a bubble of all its peers (piers?).  Not pictured is the sledge hammer I needed to break the cinderblock loose from the frozen ground.

Some folks process wood in the summer months and need, likely, gallons of gatorade.  I deal with my wood during the months the stove is running and I can sip on some scotch while I am working.  In the summer when the stove is idle I like to stroll around my woodpile in a pith helmet with a gin and tonic in one hand and a riding crop in the other as I watch the pile gain value as it loses moisture - when I am not out camping or boating or fishing or etcetera.  

Total pain in the neck, this part of the project, but it is worth it to me to have a stash at 14% instead of 18% MC.







Hope ( I mean I really smurfing hope) to build the first module this weekend.


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## Poindexter (Dec 11, 2015)

renewablejohn, doubleB, you are correct.  Case hardening iron (in bone and charcoal) introduces a tiny bit of carbon to the surface of the item, making steel and indeed changing the metallurgy of the surface of the piece.  However, padlocks and etc can be case hardened with heat only, no added carbon, just changing the temper of the surface of the original steel.  The induction hardened working surface of the Peddinghaus anvil by Rigid is another example of no change in chemistry to go with basic padlocks.

I don't know how much wet bulb depression I can get with just passive solar, but I am by golly going to find out.  Dual dry/wet bulb thermometers start at $10 on amazon...

I got up with a guy in the last couple months that makes log cabins.  He is felling standing spruce now while he can drag the logs out of the woods to his truck without getting mud on them.  Once his yard is full he will peel the bark off all the fresh logs, and then season the peeled logs for one summer on a rack that holds the peeled logs 2 feet up off the ground.  He has several acres tied up in this process, but the logs he felled a year ago that aren't acceptable for cabin building measure 20-24% MC and how much I have to pay for them depends entirely on how fast I can get them out of his way.  This (that?) wood is already well below FSP.  I am taking every stick I can get and I am going to roast them hard.

I am hoping to get this wood down to usable (12-16%MC) before July fourth 2016.  Then I will refill those modules with standing green to see if I can get that dry before freeze up.  If I can process two crops per year in my kilns I'll be selling seasoned wood when prices are good to re-coup my investment, and later sell off half my kiln modules to get yard space back and upgrade my boat.  On paper it is _possible_ , but it looks like the window to unload the kilns and refill them is really short, less than a week.

The week between summer solstice and July fourth is a really bad time to sell seasoned firewood, price is as low as it goes for seasoned wood.  I don't have a vapor tight shed that will hold 7-8 cords of seasoned wood, but it is on the event horizon; I have a written plan and cost estimate to share with the wife if I get the opportunity.


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## DoubleB (Dec 11, 2015)

Nice progress.  I admire your ambition and planning too.  

It's so unusually warm here the sight of snow on the ground is still foreign.  Enjoy!


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## Jags (Dec 11, 2015)

Poindexter said:


> In the summer when the stove is idle I like to stroll around my woodpile in a pith helmet with a gin and tonic in one hand and a riding crop in the other



First giggle of the morning.  Thanks for that literary gem.


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## BlueRidgeMark (Dec 11, 2015)

renewablejohn said:


> Come on I have been commercially solar kiln drying logs for over 5 years and have never had any examples of case hardened logs. Where on earth are you drying these logs if you think you can get them case hardened in the sahara desert.



Did a little research online.  Read some university and forestry department papers on it.  All I found was about stress in the wood, not one word about it affecting drying times.


I think it's a problem that does not exist.


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## Poindexter (Dec 13, 2015)

Got some work done yesterday.

Basic floor framing, 2x4 Pressure treated, 42x96 inch box, cross pieces on 16 inch centers.






Above the framing, a layer of water impermeable plastic, and then a layer of 23/32 CDX plywood.  I think 1/2 plywood might be enough, but it was only a couple bucks more for the 23/32...






Once everything was fastened down and trimmed up, I intentionally left plenty of slack in the plastic layer.  +55dF in the garage, plenty colder outdoors.  Bottom view, completed floor:






Not plannign to repost these over and over, 1 floor down, six to go...


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## Poindexter (Dec 13, 2015)

For the modules with the long axis North South like this one, the footers go onto the flooring this way:






And framed up outdoors it looks like this.  Top of the ridgepole is 8'3" off the deck.  I have it flat and level enough, but some trimming out to do before I can load it with cord wood...


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## Poindexter (Dec 15, 2015)

Got a 4' width of wire fencing hanging from the top of the east side.  Hanging fence on a ladder at -10dF is no fun.  Have all the pieces I need to finish the first module in stock, except for the green cordwood.

I am using 2x3" rectangle steel fencing, vinyl covered, still have to put a layer on the west side of the center wall.

I was going to staple the fencing down, but all Home Depot had was galvanized staples, then I realized steel is a cat poison too, which is why I bough vinyl covered fencing in the first place, so I went with 1x2 batten and countersunk drywall screws...


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## Poindexter (Dec 17, 2015)

iluvjazznjava said:


> Have you considered how you are going to vent it?



Responding photographically to this prescient question from back in post seven... I hung a four foot course on the west side of the center wall tonight, establishing a central air column full width, full height and ~4 inches thick...


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## Poindexter (Dec 18, 2015)

One (five) more trip(s) up the ladder to get these on top of the ridge pole.  Then two headache bars from the ground and load it up.  I ordered wood today to fill it.  Hopefully these will start going faster....


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## Poindexter (Dec 19, 2015)

Got some more work done today.

First I smoothed up the PVC castings on my gable pieces:






Then I got all those up on the ridgepole, no more ladder for now.






And I got what I am calling cheek pieces for now, they'll be &^$^& headache bars in no time I am sure.  You might also think of them as the sill plates for the rafters....


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## Poindexter (Dec 19, 2015)

Couple more ventilation approaches.

2" PVC pipe, one ten foot piece cut into 8 pieces each 15" long.  These should let air into the center column at the bottom.






And some regular shims at the bottom of the south end. When the south facing vertical wall gets plastic covered I intend for condensation running down the plastic to drain outside the module...


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## Poindexter (Dec 19, 2015)

I was planning to channel Bach's toccata and fugue in D minor at this stage, Deedle-eee! dee! doo!

But no, the boys in the band ordered boat drinks, so Jimmy Buffet it is.






My construction foreman stopped by soon after.






Wife approval factor is very very high.


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## Poindexter (Dec 19, 2015)

The construction foreman is possibly more interested in dry cordwood than I am.


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## kennyp2339 (Dec 20, 2015)

I see the plan now - I was having a hard time visualizing it, looks good and I cant wait to see your results


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## Poindexter (Dec 20, 2015)

Dang it.  Torsion.   I had this shimmed to within 1/4 bubble of level all around before I called it a day yesterday, but clearly the floor corner in the right foreground is low.

If I can put these on a reasonably immobile foundation and keep the not PT wood above the vapor barrier dry, I think a 15-20 year service life is achievable.  A module moving around this much will likely not last three years I don't reckon.  At ~$300 per I'll settle for a ten year service life expectancy.

I am going to get some 4x6 landscaping timbers today and read up on timber framing.  I want to build some kind of a skid to set this empty module on to keep it from wracking until the ground thaws.  Once the ground is thawed I can see about digging a rectangular hole and compacting gravel back up to grade level and flat, - for now I just need something temporary to keep this module from twisting itself apart.






Input invited.  Something strong enough to not flex as the snow melts and the ground thaws.  Empty module probably about 400#.


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## Ashful (Dec 20, 2015)

The way this is handled in a timber-framed structure is knee braces at each mortised corner.  Very strong, but no more so than a plywood panel gusset (eg. 18" x 18" triangle in each corner).  With both methods, the failure mode is the fasterners, whether that be nails thru plywood, or a wood peg thru a mortised knee brace.

Methinks no amount of structure is going to keep that thing straight, once loaded up with 5000 lb. of green wood, until you resolve the settling beneath.


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## Poindexter (Dec 20, 2015)

I agree on "no amount of structure", but if I leave it empty maybe I can make some kind of hammock to hang it in.  Looking at my empty boat trailer pretty hard too.  Thanks for the input.


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## Ashful (Dec 20, 2015)

Oh, if you leave it empty, you could just cross-brace it with a few scrap 1x3's.  Length has advantage over cross section, with fasteners still being the Achilles heel.  Go full corner to corner, as much as you can, after drawing that low corner in square.  Pipe clamps with temporary clamping calls screwed to structure, are your friend for squaring up a job like this.  Over-draw clamps a full turn on the hand screw, tack on the diagonals, and release clamps.


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## Jags (Dec 21, 2015)

Hmmm....once that thing is loaded up with several thousand pounds of firewood, it will morph to the supporting shape (ground or whatever).  Keeping the unloaded version square is probably a mute point.


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## Babaganoosh (Dec 21, 2015)

This is an awful lot of work to dry firewood.  I admire your drive though.


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## firefighterjake (Dec 21, 2015)

Seems like some folks go to a lot of time, effort and money to season their wood faster . . . and in some cases I wonder why they just don't give the wood time . . . but in other cases (such as this) I can understand somewhat when one lives in an area where just leaving the wood outside for a year or two might not be all that beneficial.


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## Poindexter (Dec 23, 2015)

I got the fool thing up on my skiff trailer today - thank God for boat trailer winch systems.  It settled back out to flat and square in about two hours.

I went ahead and put the rest of the rafters up just to get them off the garage floor.







So I got a few options at this point.  The wife suggested we sell the five bedroom house, it's just the two of us and the cat one of the kids left behind.  We are bringing all our food and all our cordwood up a flight of stairs we don't need.

Talked to the realtor, experimental solar kilns should be negotiable and portable, if they work good they won't hurt the property value, but still portable is better.

So one option is to sink 4 post holes into frozen dirt, 36" deep, 12" diameter, 4x4 posts, crushed rock fill, yada yada yada, holy cow.  Four holes per module, seven modules, ain't happening.

The other option is to upgrade the floor framing to not wrack on an 8 foot span when filled to 4000# and one pier block is low.

2x8 PT floor framing is a possibility.  Another option is 2 pieces of 4x6 as runners, connected with a 2x6 box down the middle.

I could build either of those, floor it, then move all the 2x4 off the existing floor as one unit, then re-use the plywood left behind on the next unit- leaving the existing PT 2x4 as scrap. This is probably the best option.  @5.67 each I would be scrapping about 30 bucks to save the other $270.

Last option is get a pair of PT 4x4s, eight footers.  Set those on pier blocks at the corners, do what I have to do for shimming, set the entire assembly I have on the 4x4s and then run some lag bolts in while everything is square.

Stewing, but I need to get cracking on this, it is almost Christmas and I don't have a single split put up for next winter.  I am about two cords behind on splitting and stacking.


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## Poindexter (Dec 27, 2015)

Looked my options over pretty hard.

I know from experience I can stack a green cord, ~4000#, on two pallets up on cinder blocks.  It will hold, until one of the pallets splits at the side cut out for the lifting forks.

How much is 4000#?  A green cord you say, but that is like 2000 pieces at 2 pounds each.  How much is it in heavy things?  Upright pianos go 300 to 800 pounds each according to google, the Steinway model D, a nine foot concert sized grand piano, is 990#.  Now it seems real.  4000# on a 42x96" footprint (28.5 sqft) is like piling eight upright pianos, or four 9 foot concert grands on one module.  

4000#/ 28.5 sqft is 140# per sqft.  Residential homes are generally built for 40# per sqft, no pile of pianos is going to work in any house I ever lived in.  Light industrial floors are generally accepted to handle 125# sqft; heavy industrial floors, 150# sqft.  So I need a heavy industrial floor.

I thought about the homes I have visited built on permafrost, where they do the three foot deep holes with compacted gravel - for 40#/ sqft loading- and most of them have the twisty jacks permanently installed on all the posts so the homeowner can go relevel the floor every spring and fall.  

I remember in Kentucky the frost line was at 24", mostly because all the fence post holes I dug had to be 30" deep.  And in upstate NY the frost line was 42" and all the house footings had to be 48" deep.  And the houses up here on 36" posts move around even at 40# per sqft.

So I accept no matter what I do, the piers my modules sit on are going to move around.  I just have to allow for that.  Then I googled up random stuff like "Why does my deck bounce when my guests get liquored up?"


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## Poindexter (Dec 27, 2015)

The wall system I have already built more or less requires a flat floor.  Doesn't have to be perfectly level, but it can't twist or my wood is coming down.  

So  I built a new box in 2x10 to the same dimensions as the original one in 2x4.






Then I put skids on what will be the bottom...






I am using "uber grade" screw fasteners by some company with a TLA for a name.  It was the only PT fastener I could find (HD only, not Lowes) that lists a shear rating on the packaging.  They are about 12 cents each when buying in bulk.  I was thinking of a certain brick house, screws are rated for 1012# shear.







Then I flipped it over and put in a central line of stiffeners...






I did the plastic vapor barrier and plywood flooring as previously documented and got the existing wall system moved over just before sundown.


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## Poindexter (Dec 27, 2015)

At this point I am over budget like a shameless defense contractor.

I am going to keep the original 2x4 framed floor module, the one up on the trailer above.  I am going to put a different wall and roof system on it that allows for it to twist as the ground thaws and my cinder blocks move.


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## therdlesstravld (Dec 27, 2015)

Just a tip for the future. Nails have a much higher shear rating than screws for the most part. Your Home Depot should have Simpson brand strong nails which is what we use for deck fasteners and hangers.

 Hangers would also increase the strength of everything. You could use regular framing screws or nails for everything except the floor joists. And then hang the joists on 2x10 joist hangers directly into a doubled up rim joist. Use longer Simpson nails for the hangers so they go into the second rim  joist and you've got something.


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## Poindexter (Dec 27, 2015)

therdlesstravld said:


> Just a tip for the future. Nails have a much higher shear rating than screws for the most part. Your Home Depot should have Simpson brand strong nails ...directly into a doubled up rim joist. Use longer Simpson nails for the hangers so they go into the second rim  joist and you've got something.



Duly noted.

I have a quote floating around my workshop I wanna share.  I wish I had read this a few years earlier.  I am about to build a module to sit on moving ground to carry a cord of wood, with a floating roof on it.



			
				A. Donald Newell said:
			
		

> Chapter one: Do not think you are limited by what you have to work with. You are limited only insofar as you allow your intelligence and reasoning to do that limiting. Accept a narrow horizon and your work will reflect that thought, but by realization of the vast possibilities open to you your scope of operations will be broadened and your work will reflect that freedom of thought and action.



How cool is that?  I wish I had read it 20 years earlier.

_Guide to Gunstock Finishing and Care_, A. Donald Newell, (c. 1949)


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## Poindexter (Dec 29, 2015)

I did add two more pieces of framing while I had the thing apart, see esp posts 41 and 43, the new pair still has the tags on it:






I originally bent all the middle section PVC hoops by taking one of the corner hoops off, bending to the same curve - but the middle pieces relaxed into a slightly different shape.  The added piece seems to be a success at holdign the same curve over the length of the unit.

I did get the plastic up tonight, fairly long handheld exposure with a flashlight inside the kiln:






And I did get four pieces put up for winter of 16/17.  I was beginning to think I wasn't gonna have any wood put up for next winter when New Year's got here.  Squeaked under the wire on that one, thanks to a branch coming down in my neighbor's yard.






Only 13,996 pieces of firewood to go to be ready for next winter.

At this point I have almost everything I need to finish a second module, and likely off work on Wednesday.  I just can't hardly bear to calculate how much I have spent on this one, though it should last the rest of my life except for the plastic and maybe a PVC pole or three.


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## sportbikerider78 (Dec 29, 2015)

I have given up on nails entirely.  I love the deck style screws that you install using an impact.  They are absolute heaven when you can't get access to an area or you are working over your head.  I'll never buy normal phillips head screws again.


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## kennyp2339 (Dec 29, 2015)

sportbikerider78 said:


> I have given up on nails entirely.  I love the deck style screws that you install using an impact.  They are absolute heaven when you can't get access to an area or you are working over your head.  I'll never buy normal phillips head screws again.


 Those coated deck screws with the star heads have a higher sheer resistance than normal house screws, they are a life saver, I remember the old say: nail things up, screw things down.


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## sportbikerider78 (Dec 29, 2015)

Oh yeah.  I would never use sheetrock screws for an outdoor project I cared anything about.  They will rust through in a short period of time.  They are SUPER cheap, but find for their designed purpose.


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## Ashful (Dec 29, 2015)

Deck screws are for decking.  Timberlocks are the way to go with framing.  Available in all sizes, even countersunk head with serrated teeth under the head for self-sinking, and they're all rated for very high sheer.

That said, I nail a lot more framing today than I used to, ever since buying a real framing nailer.  Much quicker than screws with the impact driver.


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## Poindexter (Dec 31, 2015)

Random pic I clicked on in my camera when I was downloading the day's work.  Looks like June, I had one corner of one pallet crack, about two cords of wood on the ground in 5-6 seconds.  This is why I HATE stacking cordwood on pallets.  Do notice the cinderblocks...






Work space of the day is this cavity, four pallets long.  The upright two cinder blocks on the far right have been moved, all the other cinder blocks just peeking out of the snow have been load bearing for at least one year and not likely to move very much.






I cut 24" off of each of four 2x4s and built two boxes with outside dimensions 24x75".  I'll get back to that pallet laying there in a couple weeks.






For ridgepole holders, 2 8 foot 2x4s with some pretty cheap work at the top end.






Assembled the framing looks like this, the first floor I built on well settled cinderblocks, likely to sag 1/4" in the middle, boxes and ridge supports as above, two more 8 foot 2x4s accross the top, think of a bunk bed.  If i can fit a layer of 16" splits up there 5.5" high then this module will hold one green cord.






This thing is barely pinned together, just strong enough to support the roof.  Needs a diagonal system to keep it square, and I am going to have a tussle stacking in it.






I used rope, bowlines and Spanish Windlasses for the diagonals.


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## Poindexter (Dec 31, 2015)

On to the floating roof...






I want them all to come out the same since I have 20 some more hoops to go after these five...


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## Poindexter (Dec 31, 2015)

So I got room for a full cord in here, the chunk of furring strip acting as a spreader is 17.25" long and 11" above the deck of the bunk bed.

The ridgepole is a 1x3 furring strip, just laid up there between the screws I pictured earlier.  I am going to tie some 550 cord around the ridge pole at each end, and then through the holes I drilled in the verticals so the roof doesn't blow away in a strong wind.

Gonna go have another beer while I stare at it some more...


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## Poindexter (Dec 31, 2015)

Yup, I think it will work.  Instead of q8 of PT 2x10s I am going for q4 of 1x3 furring strips tomorrow.

It has occurred to me I could register a homebuilt 16' x 42" johnboat with the state, use a veiner bit on my router to engrave the registration number on the two expensive ones (only one is built right now), and have a leg to stand on if they are ever found.


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## kennyp2339 (Dec 31, 2015)

Bro - your moving along, when are you going to stack wood in your first sections?


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## Ashful (Dec 31, 2015)

Poindexter said:


> Random pic I clicked on in my camera when I was downloading the day's work.  Looks like June, I had one corner of one pallet crack, about two cords of wood on the ground in 5-6 seconds.  This is why I HATE stacking cordwood on pallets.  Do notice the cinderblocks...
> 
> View attachment 170436


Why would you put cinder blocks under your pallets?  Of course they're going to fail, if you do that!  The reason we use pallets is that they give a 3.5" air space below the cord wood, even when placed directly on the ground.  No need for cinder blocks.

If your ground isn't level, then just shim the low spots with pavers, brick, or scrap wood.  Try to get one under the middle, and at least three down the elevated edge, or they'll fail, as you found.  Pallets are designed to carry substantial weight, when placed on continuous level ground.


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## Poindexter (Dec 31, 2015)

Ashful said:


> Why would you put cinder blocks under your pallets?



Well, how long have you got?  The short version is, like solarguy2003, I am in a running battle with ground water at my address.

I started out with pallets directly on the ground.

My wood got "dry", but nothing spectacular, and then that same wood picked up a bunch of water every time ambients got above freezing.  

Three of the last five years we get 5-7 days around Thanksgiving with daytime highs at like +40dF and then back below freezing overnights.  With pallets on the ground, I would have melting snow running downhill into my dry wood, and early in the burning season too.  The hard packed snow I have been walking on to get to my woodpile is a layer thicker than the cinder blocks are tall.  Off the packed trails, the snow in my yard is midthigh deep, about 30" accumulated.

We hit +40dF yesterday, 12-30-15.  Nice to be out there working in shirtsleeves, but as above, wood on pallets...  Never seen that in December before.  

December anomaly aside, the other annual event is the melt.  Long about mid March I'll be seeing consistent day time highs above freezing on into summer.  I need to have all the wood up by then; because the packed snow on the driveway either gets my attention, or my wife gets my attention about the puddle of icy cold water under the laundry machines.

I'll be running the stove into early May for sure.  What I can do in say early April is kneel next to my wood pile, take a glove off my hand, stick my hand in the gap between the snow and the pallet, and my hand will be literally dripping wet with condensation in a matter of seconds on the south side of the stack.  Same day, other hand, north side of the stack, I can see little tiny beads of  condensation on the skin of my hand in moments.

When my wood pile is 12%MC and there is that much vapor in the air, the vapor is going to end up in my cordwood.  I can lift the wood above the worst of the vapor layer, and this year am adding plastic to the underside of my seasoning stacks.

All of the above ignores direct pumping of water out of the ground into the stacks.  A dry, hot stack of wood, at my house, will pump water straight out of the ground into itself.  I have about a cord put up, completely wrapped in plastic on all 6 sides for the spring 2016 melt.  Hopefully it works,


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## Poindexter (Jan 2, 2016)

First, i gotta renumber.  I was gonna go back and edit all the previous posts, ain't happening.

Working right to left:






The hole in the hardpack with the junk piled in it, far right, is the home of future module one.  Second from right, already plastic covered is module two.  It is the second floor I built and the first vertical framing, but it is module two now and will remain so until the house sells.  The pallet and hole will be future module three, I am going to use two pallets for the floor and I'll get to it when i get to it.  Today, fat left, I was working on module four, the first floor I built and second vertical framing design.  Five, six and seven will appear later out past the bezel on your monitor to the further left.


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## Poindexter (Jan 2, 2016)

Put the roof framing together in the garage.  Weighs maybe 15 pounds, 40' of 1/2 PVC, 48' of 1x3 furring strip, 5 fathoms of 550 cord, 10 2.5" drywall screws and 70 inches of 1" PVC.  And 20 of 1 5/8 DWS too, sorry.






It went up no problem. 






Two Spanish windlasses at the tips, one at each end:






Had it looking good enough,






for legs.






I used the off cuts from the 1/2" PVC to make some more ventilators.  3 scraps, 2 wire ties, done.  I didn't put the pipe clamps on over the one inch pipe sections until it was up.  So far very pleased with the T beam style sill plates, I was anticipating having to run at least one, maybe two connectors through the woodpile and then have to stack around them.

Texted with my wood guy yesterday, he said he would call today but didn't.  I do want to get the two i have built loaded up to see what I learn from that before i get too carried away building more.


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## Poindexter (Jan 2, 2016)

So my wood guy is maybe coming Wednesday night.  I started loading module four, just moving already seasoned wood in the way of building module five, have a few thoughts.






The bunk bed shelf above is brilliant, if I do say so myself.  Short ugly twisty pieces that won't stack well, just throw them up top.






I was rocking until I was trying to fit two layers of wood between the Tbeams, which happen to be at exactly eye level darn it.

View from above, I can't do this efficiently with a head lamp, I'll have to finish tomorrow with sunlight.






Pretty crowded in there.  I cram every stick I can in there tomorrow and get it covered, at least this wood won't be getting any wetter if we have another mid-winter thaw.  Did you guys see the weather map for Christmas day that had the North Pole at +31dF?  Whole darn state of Alaska was above freezing except for Southeast and the Aleutians.  Easy on the oil bill, but hard on uncovered woodpiles.

For the next one I am going to lengthen the upper cross piece as shown in this primitive use of MSPaint...






I figure if i can make that 2x4 longer at each end I can attach a 2x4 end to end just hanging out there, attach the PVC hoops to it and not keep banging my head on the Tbeams.  And i got to modify the plan for module one, it needs an upper shelf capacious enough for a double dose of uglies and twisties.


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## Poindexter (Jan 5, 2016)

At a decision gate, wouldn't mind some input.

From east to west, here is my existing woodpile in the foreground, future home of modules six and seven.  That snow piled up on the north side?  Wind blown, that whole side of the stack is filled with snow in every gap between every split, I got accumulation in the gap between the parallel stacks.  Further back working to the right I have #5 framed up...






Looking from the other end, I have old splits that were holding down plastic top covering in the future home of 1.  2 is standing empty.  In the future home of 3 I have some seasoned cord wood off the stack with the worst of the snow brushed off it.  4 is loaded with seasoned wood, well brushed to get the snow off it, but plenty of mold and mildew from a damp summer.  And you can just barely see #5 at the far left.






Looking for +30dF tomorrow.  I have a solid cord completely wrapped in plastic under my deck, I am hoping it is well enough wrapped that it doesn't pick up any moisture to speak of during the melt.  I have another light cord of seasoned moldy wood sealed up in #4.  4 is open at the west end but sealed shut at the east end, the five side is sealed, the three side is open.

Once the melt is going strong, I am going to have to do something to unit four to kill the mold spores in it.  I can replace the plastic cheap, I figure a couple or five good sunny days with no rain should kill everything off.

My wood guy isn't coming Wednesday with two cords, he is coming Saturday with one cord.  I figure I'll put the new delivery in 2.

Do I keep brushing snow off my moldy splits and contaminating new construction to keep them from getting any wetter, or do I start infilling with new green splits for next winter?

I am inclined to let it ride and fill the new construction with new wood...

Came up with a curtain idea so I can load and unload without a ladder, I'll get materials on my next trip to the store.

An alternative would be to brush off and restack 6 and 7 into 1 and 3, then top and side cover.  Did I mention I HATE restacking wood?


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## Babaganoosh (Jan 5, 2016)

I had a shrink wrap solar kiln that was hitting 140 degrees daily and as high as 165. Guess what. Still grew mold.  I'm not sure you are going to be able to get rid of it.


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## HarvestMan (Jan 5, 2016)

You certainly have challenging conditions.  You look like you are "all in" with this project, but I would suggest pulling back some chips and seeing how your current structures perform.  For the blowing snow, you might get used lumber wrap  and staple it all the way down to your pallets.  You could add some kind of spacer if you want some air flow under the wrap and also leave the ends open to get some air flow. Most places just throw away the wrap and will let you have it if you don't mind pulling it out of their dumpsters.  I only top cover my stacks, but blowing snow is not a problem here.


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## maple1 (Jan 5, 2016)

Lumber wrap is used for kiln dried lumber. If used on wood that is not completely dried, it might cause problems, especially if fastened up tight and the pile isn't off the ground. Otherwise, it's good stuff.


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## Ashful (Jan 6, 2016)

HarvestMan said:


> I only top cover my stacks, but blowing snow is not a problem here.
> View attachment 171098


OT, but I often wonder how folks with stacks like this access the wood in a given stack?  Doesn't look like enough room to pull a tractor with trailer down those aisles, so how do you do it?

I left 10 foot aisles between my stacks, which obviously eats up a LOT of space I'd rather have for stacking wood.


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## HarvestMan (Jan 6, 2016)

Ashful said:


> OT, but I often wonder how folks with stacks like this access the wood in a given stack?  Doesn't look like enough room to pull a tractor with trailer down those aisles, so how do you do it?
> 
> I left 10 foot aisles between my stacks, which obviously eats up a LOT of space I'd rather have for stacking wood.


When it comes to firewood collecting, I'm in the minor leagues compared to you and many others on these sites. I cut on two properties within tractor distance of my home. I use my cub cadet tractor to get the wood back to my property where I process it with my SS and then transport it to my stacks using pull carts; I stage about 1/2 cord in my garage using either the pull cart or sports sled to get it from my stacks (100 feet from garage).  I have seven pallet rows (~ 3 cord/row) and there is 42 inches between each row - just enough to easily get the pull cart through. Let me impress everyone with pictures of my equipment .  Collecting is a fun hobby even with modest tools; I did splurge on the SS this summer.


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## Ashful (Jan 7, 2016)

If you have 7 stacks at 3 cords/ea., then we have about the same amount of wood CSS'd!  I'm at about 20 - 22 cords split, and maybe another 6 in rounds.

The primary difference between myself and some here isn't cordage on hand, but the time available for processing said cordage.  Over three years, I was able to get about 22 cords stored, while also burning at least as much.  So I was processing maybe 14 cords per year, and only taking maybe 5 - 6 days per year to do it.  That included time to fell, drag out of woods, buck to rounds, haul home (10 miles), split, and stack.

Now, I've lost my helper and ambition to work as fast.  I probably put a full day into each cord, by the time it's done.  I'd guess I've dropped from 3 cords per day of work to just 1 cords per day, but I'm able to maintain those 22 cords at my current burn rate.


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## HarvestMan (Jan 7, 2016)

Ashful said:


> If you have 7 stacks at 3 cords/ea., then we have about the same amount of wood CSS'd! I'm at about 20 - 22 cords split, and maybe another 6 in rounds.


If my memory is correct, I think I saw a picture of you on a nice tractor pulling some huge log.  So, I was really talking about big league equipment; I've seen some really nice equipment on these sites.  The only equipment I own that I consider good is my SS;  even if it is a bit polarizing.  I began collecting when propane spiked to $4/gallon and was rationed a couple winters ago.  That winter I cut dead standing and burned some CWF bricks to make it through - didn't want to do that again.  Now I just try to keep stacking so I never need to concern myself about how dry the wood is regardless of species. Your productivity is better than mine; but I do have a lot of time and just plug away.


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## Poindexter (Jan 8, 2016)

My abortive attempt to use 1x2 batten as structural elements is completed.  Still fiddling with the next roofing system, put the 1x2 batten to work as curtain rods for roman style curtains.  i didn't want to work the plastic too hard at these temperatures, but when I am working with green wood and want good airflow this should work. 

What I did was drill a hole in both ends of each batten and bend on a half fathom of 550 cord.  Batten is 8 feet, my untrimmed plastic is 10 feet wide.  I rolled under rather than over so rain will roll right off, condensate on the inside surface of the plastic will end up in the scroll.

Might need to be fastened a bit more securely, but this held just fine for several minutes.  As above, for maximal airflow I can roll it quite a bit further up and still be top covered.


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## Ashful (Jan 8, 2016)

This is an interesting project, but are you still convinced this is the easy way to season your wood and keep it dry?  Aside from the effort of building these things, and stacking in them, how often will you be replacing the plastic?


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## Poindexter (Jan 8, 2016)

Ashful said:


> This is an interesting project, but are you still convinced this is the easy way to season your wood and keep it dry?  Aside from the effort of building these things, and stacking in them, how often will you be replacing the plastic?



I took two days off the project to think about it after HarvestMan suggested I pull back some of my chips.  I am still all in.

#1, pallets off the ground is just barely enough airflow to get my wood dry enough, but the damn pallets break.  I am DONE with pallets.  So minimum 2x4 framed platforms, yup all in, building those.

#2, Restacking.  DONE.  No more restacking.  I am putting green wood in there, playing with the curtain rods and watching wetbulb  thermometers over the summer.  During burn season, I am going to pull clean dry mold free wood out of these one face cord at a time into the garage.  Every twelve hours I will be loading the stove from the garage without having to go out in the cold in my boxers and flip flops for another arm load of wood.

#3 stacking in them, this is the biggest problem I have right now.  The roof hoops on the one I am building is going to be different from the last one specifically to facilitate easy filling.  

Plastic life span, I dunno.  I am confident I can get 12 months if I start in the spring.  If I can get two years out of some of them, great.  I am using 3.5mil "clear" sheeting from H-D, $25 for two pieces 25x10 feet each.  I get a big enough scrap off each roll to use as a module end cap, or as a vapor barrier in the flooring of the next module built.  

Hoop green house roof clips is a subject i might as well touch on.  I googled a bunch and I have to go now.  BRB, relatively.


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## HarvestMan (Jan 8, 2016)

Poindexter said:


> I took two days off the project to think about it after HarvestMan suggested I pull back some of my chips. I am still all in.


I  like how you handled making the decision.  Giving pause to consider the path you are on is something most people never do.  I'm guessing your dedication will be rewarded with results that will improve your burning situation in the next year(s).  Looking forward to seeing the completed project and your results.


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## maple1 (Jan 8, 2016)

Pallets won't break if you support them in the middle too. Only takes a couple right-sized splits for each one.

But I guess you're past that anyway.


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## Poindexter (Jan 8, 2016)

Poindexter said:


> Hoop green house roof clips is a subject i might as well touch on.  I googled a bunch and I have to go now.  BRB, relatively.



There doesn't seem to be a single product for holding the plastic sheet onto the hoops that is uniformly praised by experienced hoop house owners.  The owners all seem to gripe either about the clips coming off the hoops, or how much they spent on the clips.

The most expensive clip holder I can get without having to pay shipping are the large size binder clips from Office Max, they are labeled to hold 120 sheets each and are setting me back about a buck each.  I am using four on each corner hoop, 16 clips per module, 1/2" PVC hoops. 

It seems to be enough.  I have stood out in the wind with module two after it was covered, forecast for gusts to 25mph, felt gusts i thought were closer to 30mph and saw 35mph gusts recorded by NWS overnight the next morning.  The gusts were hard enough to get the top of the verticals on module two to deflect a solid inch, it looked like the upwind corner of the floor was getting light on the cinderblock..the gust ended, the unit snapped back to square.  No popped clips, no torn plastic, and this at -15dF. 

I am sure in strong enough weather either the clips will let go or the plastic will tear.  For now what I have is strong enough.

FWIW I saved about $4000 last year off the oil bill by burning wood.  Investing some of that savings into improving my cord wood infrastructure seems like a good idea, esp knowing that oil prices will go back up some day.


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## Ashful (Jan 8, 2016)

Not trying to dissuade you at all, but on the pallet breakage, you must be doing something different than me.  I'm stacking 6 feet of fresh oak on 48" X 40" pallets, so roughly 3350 lb per pallet, and they never break on me.  I'm also stacking on a slight hill, so one edge of the pallet is elevated on bricks or pavers.  With one on each corner and a third in the middle, the pallets easily last a three year seasoning cycle or two.


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## maple1 (Jan 8, 2016)

Ashful said:


> Not trying to dissuade you at all, but on the pallet breakage, you must be doing something different than me.  I'm stacking 6 feet of fresh oak on 48" X 40" pallets, so roughly 3350 lb per pallet, and they never break on me.  I'm also stacking on a slight hill, so one edge of the pallet is elevated on bricks or pavers.  With one on each corner and a third in the middle, the pallets easily last a three year seasoning cycle or two.


 
The third in the middle is the key difference. I also don't have any break. They will rot if they are lying on the ground.


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## Poindexter (Jan 8, 2016)

I have half a cinder block under each corner of every pallet.

Started out using splits of cordwood when I Iifted the pallets out of the dirt, looked kinda trashy.

Besides a third cinder block under the middle, another option would be to tack PT 2x4 on the outside edge of each pallet if a fella liked running a hammer more than a shovel, money would be about the same.  Another option would be to lay used RR ties on grade, level those when the ground is thawed.  Pair of RR ties 42" apart will support two pallets with no breakage loaded to 2200# for many years.  After many years when the pallets break, the RR ties will be barely warmed up.

Done with it.  My favorite elective in college was Archaeology Field School, got the shovel edges to prove it, but banging out square flat bottom holes and leveling the bottoms of all those holes to each other is not that much fun.

I looked seriously into building one large kiln to handle nine cords at once.  On a 12x24 footprint with the wood stacked 8' tall... I would have to build a foundation for 50,000# including anticipated snow load and my soil only supports 1000# per sqft.  So minimum 50sqft of footing under 288sqft of floor, I haven't saved enough on the oil bill to think about that too serious and it will never be easy to get that much wood in and out of a floorplan that small.

One of the unique things about my location is the ground is so darn soft.  2,3 and 4 thousand pound per sqft ratings are not uncommon in the lower 48, I am on a mix of sand and glacial silt.  If your ground can handle 3000# per sqft you can put three tractor trailers, loaded, on the footings I need for nine cords of wood with snow on top.

Or I can build a thing that is allowed to move around on it's piers...

Don't mind the side discussions.  I have put a lot of thought into getting the cleanest driest wood I can out of whatever I build.  I am looking for a multicord stash of mold free splits at 12% MC per electronic gizmo seven months from now, and I want the same structure to keep all that stash dry and mold free for however long it takes me to burn it without re-stacking.


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## Ashful (Jan 8, 2016)

Definitely a challenging environment!


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## MiserableOldFart (Jan 8, 2016)

I started to build one,  a small one based on an old 4x8 stair landing my sister replaced at her house.  I built the frame then got lazy, but now I threw a tarp over it and it has excellent southern sun exposure, and is open E/W for ventilation.  Original plan was more ambitious but it's something anyway.
Stacked loose, it probably only holds a little over a half cord.













Dryer



__ MiserableOldFart
__ Jan 8, 2016
__ 2


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## Poindexter (Jan 9, 2016)

MiserableOldFart said:


> I started to build one,  a small one based on an old 4x8 stair landing my sister replaced at her house.  I built the frame then got lazy, but now I threw a tarp over it and it has excellent southern sun exposure, and is open E/W for ventilation.  Original plan was more ambitious but it's something anyway.
> Stacked loose, it probably only holds a little over a half cord.



I tried a similar thing when I still had pallets directly on the ground.  Stacked loose i had a pile 4 wide by 4 tall, about 20 feet long.  I covered top and south side more or less as above, it worked ok.  It worked noticeably better when I covered the east and west end also, leaving just the north side open.  I do have consistent twilight breezes since I am between a river and a ridge, breeze out of the east in the AM and out of the west in the PM.  I think at my location I was getting enough breeze at the twilights to turn the air over, but capping the ends let a little more heat build up in the wood.

Also, for other far northern folks, appearance/ wife approval factor is a significant driver of this project.  If I had enough room behind the garage out of sight of the house I probably wouldn't do this.  If I had enough acreage to hide my woodpile I would do elevated pallets, parallel stacks, and then cover top and most of each side with wide plastic, like 10-12 feet wide so the plastic would reach from about knee high on one side, over the top and back down to knee height on the other side.  Get some plywood scraps or etc under the plastic at the top of the stack so water doesn't puddle, throw some old tires up there to hold the plastic down and forget about building all this mess.  

Long about March pull enough wood off for the rest of the season, re-stack that somewhere that it won't pick up any moisture during the melt before burn season ends, and spend money like this on upgrading your fishing boat.

It'll be an ugly pile, but it will work good, and be cheap.  Just the wife won't like looking at it all year probably.


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## Kristen (Jan 9, 2016)

Poindexter said:


> There doesn't seem to be a single product for holding the plastic sheet onto the hoops that is uniformly praised by experienced hoop house owner



My worry about your hoop-houses is that logs may "fall" and damage the plastic (as compared to a wider poly-tunnel, or an even wider multi-span polytunnel used more like a barn but with solar drying  )

That apart, I wonder if this would work instead of clips?

Over this side of the pond I see tunnels (more often cloches, but I've also seen it on single-hoop tunnels) with a string / thin-rope attached from the base of the hoop on one side to the base of the adjacent hoop on the other side i/e/ diagonally across the plastic between two hoops. One advantage of this, when growing crops, is that the plastic can be slid up, under the rope, to provide ventilation and due to tension in the rope it stays in place until pulled back down again.

My Googling failed to find a good photo, but hopefully this one demonstates the idea


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## Poindexter (Jan 9, 2016)

Kristen said:


> My worry about your hoop-houses is that logs may "fall" and damage the plastic (as compared to a wider poly-tunnel, or an even wider multi-span polytunnel used more like a barn but with solar drying  )



Well, you earned a "P" for prescient there.  See below.



Kristen said:


> That apart, I wonder if this would work instead of clips?
> 
> Over this side of the pond I see tunnels (more often cloches, but I've also seen it on single-hoop tunnels) with a string / thin-rope attached from the base of the hoop on one side to the base of the adjacent hoop on the other side i/e/ diagonally across the plastic between two hoops. One advantage of this, when growing crops, is that the plastic can be slid up, under the rope, to provide ventilation and due to tension in the rope it stays in place until pulled back down again.
> 
> My Googling failed to find a good photo, but hopefully this one demonstates the idea



I may try building one of those just for the heck of it.


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## Poindexter (Jan 9, 2016)

So I got module two filled today.  Pretty nice spruce.  I brought some of it indoors to meter tomorrow or the next day, I am guessing 16-18%MC, it's really light.






Lots of wasted space up top.  I meant for the easy splits to end below the rim of the headache bar 2x4 so if the ones I put in from up on the ladder get to shifting they won't fall down and tear my plastic.  The ones pic'd below on the right follow the plan, the ones on the left show the risk of being over enthused, as @Kristen predicted.






Lots of wasted space in the top.  I think the bunk bed style shelf like I put in module four (see posts 64 & 73 above) is the way to go for both best use of space and minimal risk of shifting logs tearing the membrane.

I did fit 0.82 cords in there.  I have been reticent to predict how much I could fit, it comes down to how much wood fits in cross ways at the top.


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## Poindexter (Jan 10, 2016)

I did account for the canary.   Here is a pic with me standing in future #3 looking west into the south end of #2.  That yellow X?  That area will never get any direct sunlight on it.  Once three is built and full it will be shaded all morning, shaded by its neighbors to the south at mid day, and never any afternoon sun in the shade of its neighbors to the west.  This is going to be the wettest wood in my stacks.






So I built the wee boxes.  You can kinda sorta see them in the previous post if you enlarge it and look real real careful maybe.  Before I build and fill three I got to drill (and likely weigh) the splits in each of the canary cages on the east side, and then run 550 cord through the drilled holes in the canaries and out the single canary cage on the west side.

Long about July 4th or so I'll tug the canaries out from under the stack from the other side to see how I am doing MC wise.


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## Poindexter (Jan 10, 2016)

Covered the south end of two and left just a little scrap edge on the big piece....






So most of the extra from my ten foot wide plastic covering my eight foot module ended up on the north end...






When i get module one built to the north of module two (this one) I am going to try to connect them thermally via overlapping roofing plastic so I'll have a single convection unit 42 inches wide and 16 feet long, instead of 2 8 foot units.


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## Poindexter (Jan 10, 2016)

I need to give a shout out @Knots 



Knots said:


> This. for the most part the sun would extract the moisture from the wood during the day, and then when the glass cooled at night the moisture would condense and it would "rain" inside.



I too have had water drip off the ceiling onto me when visiting commercial greenhouses.  That won't do.  

The Wife Approval Factor (WAF) on the semicircular roof cross section (like a Quonset hut) was very low.

I can have shipped in special greenhouse plastics in custom cut sizes with a coating on the inside that is supposed to help water droplets flow instead of falling.  I might have to upgrade the cheap Home Depot plastic I am using for now in the future, but I needed a different solution.  Plus, I figured the commercial greenhouses are using it already and it doesn't work great on semicircular roof cross section.  Also, the membrane offerings I see have a bunch of UV blockers in them.  I want to let UV through to heat up the wood.  I am building a darn greenhouse, not raising orchids.

There are essentially three categories of Gothic arch.  The classic standard is as wide as it is tall.  There are 'fat' ones, wider than they are tall, often called Tudor style, like this one: http://www.hoopbenders.net/ .  WAF on the fat one was low, but you could cram a lot of wood in there if your wife can live with it.  If you are going to use schedule 40 PVC for that you will probably have to heat the hoops (outdoors) and bend them on a jig, but you could use straight pieces for the legs. 

Classic or equilateral style Gothic arch cross section, exactly as tall as wide, as thoroughly explicated on wikipedia, got a moderate WAF.  https://en.wikipedia.org/wiki/Gothic_architecture#Equilateral_arch 

So I ended up with a skinny Gothic arch cross section, taller than it is wide, and a high WAF.  Now I just got to figure out how to use the space efficiently.  _Hopefully_, with the flattest part of ceiling having a 12:12 pitch I'll get condensation running down the plastic rather than dripping back onto my wood.


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## Kristen (Jan 10, 2016)

Poindexter said:


> you earned a "P" for prescient there



Sorry about that 



Poindexter said:


> I too have had water drip off the ceiling onto me when visiting commercial greenhouses. That won't do



I'm not sure that matters, although I'm no expert.  Whilst I expect that it is better avoided, the condensation on the plastic is from water that has escaped from the middle of the log. It drips down onto the surface of the pile, and evaporates again (tomorrow); I am doubting that any/much is reabsorbed, not back into the centre of the log and nothing like as much as escaped from the polytunnel, and I think that only in an overcast, damp, weather period might it be reabsorbed at all - but then the next sunny period will re-evaporate it.  It won't take much sun, with a polytunnel, to raise the temperature enough for that, and with a through-draught that water vapour will escape.

My barn is not the same in terms of "solar oven", but it has a tin roof which gets very cold (relatively) and that causes condensation. Never noticed it being a problem with logs on top being "wet", but I do have good through-draught in my barn.

Thought: Put a container on top of the pile and catch the condensation. I guess you would need a funnel and a bottle, rather than a tray, so that it doesn't re-evaporate easily.  I know what you mean about greenhouse "rain", but I don't think it will amount to much.  Happy to be proven wrong though


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## Knots (Jan 10, 2016)

If I was building a greenhouse specifically for wood storage, I would try to get that warm wet air pumped out in the late afternoon.  That way the water content inside the building should go down over time.  Or at least that's my line of thinking….


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## Ashful (Jan 10, 2016)

Knots said:


> If I was building a greenhouse specifically for wood storage, I would try to get that warm wet air pumped out in the late afternoon.  That way the water content inside the building should go down over time.  Or at least that's my line of thinking….


Same thing most woodworkers do with their solar kilns.  They try to find the optimum amount of passive ventilation, moving out sufficient moisture, without losing all their heat.


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## Kristen (Jan 10, 2016)

Ashful said:


> try to find the optimum amount of passive ventilation, moving out sufficient moisture, without losing all their heat



renewablejohn posted in another thread that he has a multi-span polytunnel for drying wood, and that is erected on a hillside, so the hot air naturally rises during the day and draws the moist air out of the "top" end.  Sounds ideal to me 

https://www.hearth.com/talk/threads...od-working-awesome.129149/page-2#post-1744430


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## Poindexter (Jan 10, 2016)

Kristen said:


> renewablejohn posted in another thread that he has a multi-span polytunnel for drying wood, and that is erected on a hillside, so the hot air naturally rises during the day and draws the moist air out of the "top" end.  Sounds ideal to me
> 
> https://www.hearth.com/talk/threads...od-working-awesome.129149/page-2#post-1744430



Yup yup.



renewablejohn said:


> Our commercial solar kilns are 8mtr x 25mtr with no fans. Instead it is designed 90 degrees to the prevailing wind open at each end but the important part is the ridge is not horizontal but has a 1 mtr slope over the 25mtr length. This is important as it can give a a 10C to 15C difference in temperature from one end of the tunnel to the other creating a strong convection current taking the moisture out of the tunnel.



You guys are getting ahead of me ;-)  

I found a picture of such a commercial kiln, with 1 meter rise to the ridgepole along a 25 meter span.  Without the context, they are kinda funny looking, and the WAF is low.  Clearly a brilliant idea, didn't bookmark the file to add it here.


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## Poindexter (Jan 10, 2016)

I am going to pontificate a little bit.  I have been trying to stay away from acres of text to let the pictures do the talking.

I do appreciate the input along the way, two heads are better than one.

Some parameters I am working with local to me that may not apply at your address.

#1.  I have no trouble getting my wood dry.  Everything I have split and stacked on May 15th, covered on top, open on the sides is going to be very burnable, low to mid teens MC by July 4th.  You probably don't have 20 hours of sunlight day after day that time of year....  So I know from experience I can fill all these modules with freshly split green as possible wood the night of May 14th, roll up the Roman curtains I was fooling with the other night so all my stacks are open at the sides, and go into July 5th with burnable wood.

#2. I do have enormous trouble *keeping* my wood dry. Some time between July 5th and August 10th the clouds roll in, the rain starts, and then in late September the rain turns to snow.  I think I am good for keeping rain and snow off just by rolling the side curtains down.  Keeping water vapor out during Jul-Aug-Sep is something I'll have to figure out when I get there.

Then we get the winter time melts, usually 3-5 days around Thanksgiving and in 2015 a couple days around Christmas of daytime highs above freezing.  I think I am good on those.

Then there is breakup, when the ice on the rivers "breaks up" and flows out to sea, just before spring.  Enormous amounts of water vapor in the air, and puddles of liquid snow collecting in all the low places.  Break up will start in mid March, but I'll be running the stove into mid-May.  I think I can use some batten strip between the PVC poles at the bottom to connect the plastic roof sheet directly to the floor framing to minimize water vapor intrusion then.

I do not have WAF for a sloped ridge pole, but I do have wife approval to not level every single module to each other.  Given the contour of my lawn, some ridge poles are going to be higher than others, I will be putting in some ridge vents.

I am going to learn how to use wet bulb thermometers this coming summer.  While I don't "need" to speed the drying process, I am interested to see what I can do with a green cord split and stacked on July 5th.

If WAF was not a factor in this project I would probably go with a much wider flatter Gothic arch, use knowledge like this to utilize schedule 40 PVC for the hoops : http://www.pvcworkshop.com/bendpipe.htm , and definitely utilize a sloped ridge pole.


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## Poindexter (Jan 10, 2016)

@Kristen and @Knots and @solarguy2003 are all three kinda stabbing at how water vapor moves around during sunlight hours and how condensate behaves on the overnights when convection slows.

I don't know how this is going to work.  That's why the title is "experimental" rather than "proven."

The step forward I am taking from solarguy2003's work is dispensing with fans.  I am going to try to make this work just by changing the size and location of vents while monitoring wetbulb thermometers scattered around the interior.

If I have to get fans I will at least go with solar panels and 12vdc fan units, but I am going to put that off as long as possible.  If I have to go to fans I anticipate placing them at the ridge vents with the shortest possible wiring runs and then manually adjusting the air intakes from ground level.  I'll orient the solar panels so the fans kick on and run hardest as late in the solar day as possible when humidity inside the units should be at maximum, and right before the cooling/condensing phase starts.

One thing I have noticed is the temperature of the plastic membranes tracks ambient air temp within 10-30 minutes.  When I bring a split from -20dF outdoors to +55dF in the garage it takes two days for the split to warm up all the way through.  So roughly a split is at least two orders of magnitude a better heat sink than the plastic membrane, potentially three orders of magnitude.

If I am starting with green wood stacked in say February and seal it up, any water vapor I get during sunlight hours will condense on the wood at sunset, unless I can get it pumped out.  In July, once the wood is warmed through, at sunset the membrane should cool faster than the surface of the wood so the vapor should preferentially condense on the plastic- and hopefully drip on the lawn rather than my splits because of my roof pitch.

This year I am going to keep all the sides open on my green stuff until the stacks start moving, indicating capillary flow is completed and I have reached FSP.  Then I'll see about cooking some of them.


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## Ashful (Jan 10, 2016)

WAF is highly over-rated.


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## Hasufel (Jan 10, 2016)

Ashful said:


> WAF is highly over-rated.


Didn't I see that on Jeopardy? "I'll take Famous Last Words for $100, Alex!"


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## Poindexter (Jan 11, 2016)

@DoubleB @renewablejohn @BlueRidgeMark re: casehardening, I found a link thingy:

http://www.wood-database.com/wood-articles/drying-wood-at-home/

specifically:



			
				wood database dot com said:
			
		

> *Drying defects*
> But kiln drying may also introduce internal stresses into the wood—particularly if an improper kiln schedule is used, or if corrective measures are not employed—resulting in a condition known as *case-hardening*. This defect is caused when the outer shell begins to dry faster than the core: the shell tries to shrink, but is inhibited by the still-wet core. If the moisture difference between the core and the shell is too great, the shell can dry in a stretched condition. Later, as the core eventually begins to dry and shrink, the condition is reversed, and the stretched shell prohibits the core from completely shrinking. In extreme instances of case-hardening, the core can split and check in an irreversible condition called *honeycombing*.



I think what is happening to folks in the UK and there was a recent thread from a guy in New Hampshire of Vermont too, is firewood is getting pulled from at least _some _kilns after the split is casehardened, but before the wet inner core finishes kiln drying.  So they are paying good money for wood that is dry on the outside but still over 30% MC on the inside.

Two possible solutions.  One, longer kiln time for the water in the still wet core to diffuse through the dry outer shell.  Two, air dry the wood to FSP first, then kiln it. 

Given my very brief summer, I will be going from standing green to FSP top covered (takes about two weeks locally with the birch and spruce we have to choose from), then close up the kilns and crank up the heat.  If I had a long enough summer sunshine season I would be _tempted_ to just crank up the heat in closed up kilns from the get go.  But I don't have room for two years of wood on my tiny suburban lot.  If I don't get this stuff dry this year I am heating with oil next winter.


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## Poindexter (Jan 11, 2016)

The most recent American example is in central NH: https://www.hearth.com/talk/threads/kiln-dried-wood-reading-30-moisture.151737/



			
				nhcwb said:
			
		

> I ordered a cord of kiln dried wood ...split a big chunk and tested the fresh face, only to get a reading of 37%...[seller] stated it sounded fine to him and that the reason his wood burns well is that it's bone dry on the outside but still wet on the inside which makes it burn longer.



This is what I want to avoid and might be incorrectly referring to as a case hardened split.

Also FionaD from Scotland in this thread: https://www.hearth.com/talk/threads/seriously-thinking-about-giving-up-on-burning-wood.149234/



			
				FionaD said:
			
		

> I've measured some 'kiln dried' splits up to 45% at their core!



Whatever the correct name is for splits in this condition, case hardened or other, I can't afford to make nine cords of them this summer.


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## Kristen (Jan 11, 2016)

Poindexter said:


> Without the context, they are kinda funny looking, and the WAF is low



Any chance to screen the log storage area from the wife?   We have a "bit around the back" where I grow the vegetables, and it has pallets of not-used-bricks etc.  For me its definitely not an area to be On Show, and I'm lucky to have a screen (tall hedge) between it and the house


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## DoubleB (Jan 12, 2016)

Poindexter said:


> Whatever the correct name is for splits in this condition, case hardened or other, I can't afford to make nine cords of them this summer.



Roger that.  Especially with such a short drying season, I sympathize with you.  

If the comparisons to lumber drying have given you caution, maybe one bit of encouragement also from lumber drying is that some people claim solar kilns help alleviate case hardening, because each evening they cool down and allow the shell to gain some moisture and even out with the core (unlike conventional kilns that crank full-time).  To the extent this is true, your kilns may share the same benefit and potentially help make sure you dry more evenly.

Of course that's here in the lower 48 where we at least get 6 hrs of darkness in June.  Don't know about AK where you don't get much summer reprieve from the sun!


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## Poindexter (Jan 23, 2016)

First build of the mark 3 vertical framing went up yesterday.  I dispensed with the central vertical wall and then put in an upper bunk style storage space specifically to maximize the height of the double thick stack below.







Here is another view from standing inside the unit, the headache bar on the right is a carryover from Ur to keep the roof shapes the same, on the left is part of the floor for the upper layer:






And sunlight!! WooHoo!  The sun cleared the shrubbery between the houses of my two neighbors to the south on the 18th of Jan, I am getting about an hour of direct sunlight every day now.

I loaded the top hamper or upper level or what have you without a ladder, just standing on the empty lower deck.  Only got 0.136 cords up there, but I am calling it a win.  When the branch I cut off the outgoing Xmas tree turns brown it will be a clue to get out the moisture meter.


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## Poindexter (Jan 23, 2016)

For now I am caught up splitting and stacking.  I used 7 offcuts of 1/2" PVC to make a bottom vent on this one.  Intuitively I think it is likely useless, but it keeps those pieces out of the landfill for a couple years.  Plenty of extra membrane from the module on the right to overlap the roofing and make these two adjacent modules function as one convective unit.






I have another cord of "dead standing fire killed light it with a match" spruce coming Monday, I expect it will measure 20-25% just like what is already stacked, same forest fire, different cutter.

Once I have the current module filled up, left over fire killed spruce will go in the upper bunks of the higher numbered units yet to be built to the east.  Like this one, #5, the last unit built with Mark II vertical framing and henceforth known as "that SOB #5".  The third time I put a ridgepole on it the plastic went on.  I look forward to taking a chainsaw to that SOB someday.






Finally I found someone cutting green spruce on Craigslist.  Once the incoming firekilled spruce is stacked and covered I plan to bring in three cords of green spruce to finish filling units 5-6-7 (and 8) to see what this plan can do with live sap up trees.


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## Poindexter (Jan 23, 2016)

And there is a new hope.  My inexpensive membrane from Home-Depot seems to be good enough.  I started seeing these replacements for Jack Frost's merry S curves on January 18 when the sun was high enough in the sky to clear the shrubbery of my neighbor to the south.  Day time highs, Jan 18 to 23 inclusive were (Farenheit) 7.2, 11.1, 0.1, 4.1, 5.2 and -2.7.

Minimum I am getting 20.9 degrees F of solar gain at +11.1dF:






All those wee bits of ice are on the inside of the plastic membrane.  The round ones make my heart pitter patter, those aren't from Jack Frost, those are from Mr. Sun.

Not that I think the MC of my stacks has changed at all yet, what with a seven day high temp of +11dF, but the potential, my gosh, with a month at +70dF to warm the wood through and a week of highs in the +80dF range I should be seeing dry bulb temps inside the kilns firmly up into three digits.

Jees, if I hit 120dF drybulb and 80dF wetbulb consistently the week between solstice and July 4th, it boggles my little brain,  3.3% MC equilibrium point, assuming I don't lose any ground during the four hours of twilight we get every night then.

Thank you for publishing that table USFS.  http://www.fpl.fs.fed.us/documnts/usda/ah188/chapter01.pdf , page 26.

Yes, three point three.  @BKVP  (channeling Yoda) will have a cow.  "Dryer is better I said." "Typical homeowners struggle to get to 20% MC I said."

EDIT: 20.9 degrees F gain, and the latent heat of crystallization.  Shazam!


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## Poindexter (Jan 29, 2016)

Here is the Mark III vertical framing almost full.






And I got 1.005 cords in that sucker.  Finally.  It has been an unspoken goal all along to fit at least 1.0 cords on the 42x96" footprint.






So Mark III vertical framing (or better) on the remaining four units to build and I'll be built out.  I got figger out how to put a floating roof on one of these...


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## Ashful (Jan 31, 2016)

That is one fancy pile of sticks, Poindexter.


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## therdlesstravld (Feb 1, 2016)

The way you frame things interests/scares me. Pretty when all filled up though!


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## Firefighter938 (Feb 2, 2016)

therdlesstravld said:


> The way you frame things interests/scares me. Pretty when all filled up though!



 Yep, that is some unique framing.


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## Poindexter (Feb 9, 2016)

therdlesstravld said:


> The way you frame things interests/scares me. Pretty when all filled up though!





Firefighter938 said:


> Yep, that is some unique framing.



Well, lets talk about framing.  It took me a week to swallow my pride, but the point of this thread is to get help from people who know what they are talking about.

So framing.  Cheapest possible build.  I started with two pallets (no side cut outs for forks) and six cinder blocks already on the dirt. 






You can kinda see bottom front right I already got 1" pipehangers on the corners, those get tricky to install once the floors are on the cinder block.

Bare framing from the long edge:






You can see there is four verticals at each end.  There is no screw or bolt or nail or glue or anything else holdign the 2x4 down to the pallets, just gravity.

Here is an end view of a different unit, same design, showing the ends of all seven of the 2x4s running left to right in the pic above:






Tracking?


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## Poindexter (Feb 9, 2016)

Then I put in diagonals.







And started filling with cord wood.






I got .135 cords up top.  If it was fresh green birch at 4000#/ cord we're talking 540 pounds.

The plastic on the floor is plenty loose and 2 layers.  I don't expect it to last multiple seasons, but it ought to last one.

Then i filled up the bottom...






I don't think I am Bob Villa, but I think this is strong enough.  It is a temporary structure on cinder block.  The framing is supporting up to 540# of cord wood, 10 poles of 1/2" PVC, one sheet of 6 mil plastic 10x20 feet, 8 binder clips from OfficeMax.  

I don't know what the possible retained snow load on the plastic membrane is, haven't gotten much snow lately.  In summer I would be hard pressed to store 1 pint of water on the plastic roof of a single unit overnight.

The 540# of wood up top can be represented as a point load pushing down in the middle, that load is going to want to push the feet apart.  There is more lateral loading from the wood on the lower deck also tending to push the feet apart.  So far my Spanish windlasses are holding.

The empty unit i could pick up and carry away from the pallets.  Loaded, the lateral loading from the wood on the bottom deck seems to give me enough torsional resistance that I am not thinking about upgrading.

This would undoubtedly be a stiffer stronger unit If I tacked three sheets of plywood to it, but it would seriously cut down on air flow.  All I really have here is a PVC and 6mil plastic tent that holds 540# five feet up off the ground.

I think my most likely problem is going to be end splitting on the horizontal 2x4s as the moisture content varies dramatically over the course of a year.   With a week of thinking about it (and the advantage of walking around the physical structures with a sledgehammer just making sure) the only thing I have thought of that _might_ make a difference is to paint the ends of all my 2x4 with some latex paint so that all the moisture moving out of the framing is radial and tangential with a minimal longitudinal displacement.

I think.  Please do bring on the informed critique.


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## therdlesstravld (Feb 12, 2016)

I didn't mean to insult it's just that the framing is well, wrong. Your completely relying on the nails or screws to hold the weight of the upper tier. It's fine, albeit wrong, to build it like that when dealing with just containing your stacks of making a play to hang your plastic. But the upper area your loads aren't carried down to the base they are just floating up there held to the vertical framing with your fasteners. 

Think of it like this. When you build a second story to a house you first build a wall with bottom plate, studs and a top plate. Next you lay the floor joist on top of the top plate making sure to land them over top of the first floor studs. What this does is translate all of your load onto the top plate then onto the studs and finally the bottom plate and foundation. Right now your translating all of the weight into your fastener.

Best of luck and if you have any questions I'll do whatever I can to help you out.


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## Poindexter (Feb 20, 2016)

Not insulted.  I tried it "that way".  this would be I guess Mark IV module framing.  This is module #8, so far I have six of eight built and five of those six filled up for next winter.

I figger I'll build the remaining two this way also (module numbers 6 and 7).  I juggled the 2x4 lengths a little bit to fit a bit more than .135 cords up top.


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## Dantheman300z (Feb 20, 2016)

Enjoying the thread.  Wish you were my neighbor.


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## Poindexter (Feb 28, 2016)

Built out.  I got ribs and membrane on 6-7-8 today.  I was rushing to get the membrane up since the forecast called for rain today.  In Alaska.  In February.











I think I might have an avatar worthy image here when I take the time to pull the wrinkles out of the membrane.

Couple notes.  On the earlier units I used galvanized pipe hangers to hold the PVC 45s down to the ridge pole - I was cementing 2 45 onto a a short piece of 1" diameter pipe, 3 7/8" worked good for me.  

Zinc is a cat poison, copper is not, I switched to copper pipe hangers to not poison the cat because I have a right lot of "window frost" collecting on the inside of the membrane in shoulder weather.  I discussed this a little bit in the operation thread, with a link to a CalTech physicist's hobby ice crystal page.

My yard- my latitude - my solar exposure the window frost - the ice accumulating on the inside surface of the membrane- runs all the way down to the lawn on the inside surface of the membrane without dripping off the ceiling onto the wood very much - but it only takes a little tiny bit of zinc to kill a combustor, so I switched to copper.

FWIW this last iteration of framing, Mark IV is tall enough that I am using full length ( ten foot) PVC poles for the ribs and not having to cut any length off them before they go on.  I am cramming every scrap of wood up top I can.  These last few modules will hold slightly more than one cord, but not 1.2 cords I don't think.  After giving up 18% shrinkage in seasoning I do not think I will be getting a full seasoned cord out of any single 8' unit.

Out of 8 units I have 5 different designs in use, but this last one that I made three of is the way to go I think.  I can make them cheaper, but some of those less expensive ones that I saved 30-50 bucks on two months ago are and will continue to be a pain in my neck until I upgrade them to Mark IV.  I have pretty well maximized internal volume and storage capacity, and maximized ease of use without resorting to special order non standard materials.

I plan to post up working drawings of the Mark IV design so anyone can build however many they want - or start there and build a better one.  Once that is up I -intend- to ask the mods to close this thread so we can all get on with our lives.

Solar wood kiln operation thread is here: https://www.hearth.com/talk/threads/solar-cord-wood-kiln-operation.152699/


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## Firefighter938 (Feb 28, 2016)

I've enjoyed watching your progress.


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## Coalescent (Feb 29, 2016)

I am in awe, Poindexter. I'm finding myself wishing there were blueprints I could follow to construct these myself to get a jump start on drying out the wood I'll need starting next winter. Very impressive, sir. Thank you for taking the time to detail the steps you've taken and the iterations you've made to your concept.


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## Poindexter (Mar 1, 2016)

Coalescent said:


> I am in awe, Poindexter. I'm finding myself wishing there were blueprints I could follow to construct these myself to get a jump start on drying out the wood I'll need starting next winter. Very impressive, sir. Thank you for taking the time to detail the steps you've taken and the iterations you've made to your concept.



Briefly the four verticals for the lower level at each end are 68".  The two verticals at each end for the upper level are 24".

The header and footer for the upper level are 14" each.  You'll need one piece of 2x4 11" long at each end for the ends of the upper shelf.  The footer for the lower level is 42", the header for the lower level is 35".  Floor is still 42" wide by whatever for length, I haven't gone greater than 8 feet long per module myself.

Whatever your length is you'll need seven pieces of 2x4 that long, you can see six of them in post #123 above.  The seventh is the ridge pole, not yet installed in post 123.  Those tiny short pieces between the top box and not yet installed ridgepole, 6".

On the ridge pole I am using 1" PVC fittings, a piece of straight pipe 3 7/8" long, with a 45 elbow cemented on to each end.  Copper pipe hanger to fasten those to the top of the ridgepole on 24" centers.

Each 10' long 1/2" diameter PVC pole fits into the open end of a 45 degree elbow, one drywall screw in the 2x4 68" up, and then into a galvanized 1" pipe hanger screwed into the floor joist.   I have been drilling through the pole 45" from the top to make install easier.  I am using galvanized screws and pipe straps BELOW the level of the plastic between the flooring and joists, but not above that level.

I am putting in diagonal braces - Spanish windlasses - every second or third unit.  I think 550/paracord is adequate, but if you have heavier scrap taking up space use it.

If money is no object you can get SS screws, but they are twice the price of regular painted DWS.

Best of luck, I have two cords of green spruce splits getting dropped tomorrow and 8# of beef committed to becoming pastrami after a six hour smoke on Saturday that I'll need to deal with daily for the rest of the week.  So maybe more detailed instructions next week sometime...


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## Coalescent (Mar 1, 2016)

Poindexter said:


> Best of luck, I have two cords of green spruce splits getting dropped tomorrow and 8# of beef committed to becoming pastrami after a six hour smoke on Saturday that I'll need to deal with daily for the rest of the week.  So maybe more detailed instructions next week sometime...



Thank you! I look forward to making my own attempt soon. Many things coming together to bring wood heat back to this old house...

I look forward to the possibility of more detailed instructions after the delicious transformation that beef is undergoing. Great shots you've included in this thread; that helps, too.


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## Poindexter (Mar 27, 2016)

edge-of-the-woods said:


> Is that hooped-over 3/4" PVC going to be able to stand up under the weight of any snow you're going to get over it?  Or are you moving it someplace else during snowfall season?




Apparently yes.  Finally got one measurable snow fall since November.  About two inches in 36 hours.  I let all the side curtains down to keep blowing snow out of my stacks, my roof is steep enough that the plastic and hoops held up just fine.  No experience with freezing rain yet...









iluvjazznjava said:


> So looking again at your description ... I assume by "passive" you mean no sort of mechanical ventilation?  I can't quite envision how your condensate removal actually functions. * Is the idea that the condensation on the inside of the plastic will run down and drain at the bottom on the sides?*  If so, my experience with greenhouses tells me that may not work, since condensate on the inside of the roof (if vents weren't used) just tended to drip right back down when things cooled off at night.
> 
> I hope it works though - would probably keep things simpler.



I have observed interior condensation running down the inside of the plastic from ridgepole all the way to the ground now.   The plastic does need to be fairly taut.  If the plastic membrane has sags in it the condensate will get soaked up by whatever horizontal 2x4 the membrane is sagged against.

The cheap plastic membrane I am using does expand or stretch in warmer temps.  Likewise, it contracts in colder temps.  So far I am having to re-tension all the membrane when the temp changes about 40dF or so.  Hoping to get it taut at +70dF later this spring, maybe May or so, and not have to fool with it again until temps drop below freezing in September.


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## Poindexter (Apr 26, 2016)

I do have some sagging going on.  When these are next empty I am going to have to put in some plywood scraps to hold the uprights square.


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