To combust, or not to combust, that is the question.

[kwa]

Hello,

Love the forum. Lot of good info. First wood stove and first post.

I have read all kinds of technical manuals on various stoves. I still have not picked the exact one yet but here's my situation.

All speak of clearance to "combustible walls" and how to reduce this space with proper shielding, etc.

I recently tore out a zero vent fireplace in a small weekend home I just bought and will be replacing it with a wood stove.

My intention is to build up the hearth to the manufacture R-Value with the final layer being stone or tile. This I understand and does not seem to be a big challenge as long as the coverage meets specs for the particular stove.

My general question is this:

Instead of placing a shield with 1" spacer off the existing combustible wall I would rather just build a new wall 1" away from the existing wall and make it out of metal studs, durock, and tile or rock. I would do this all the way around for a 24" alcove installation. Half the stove would probably be in the alcove and half out. Left of the new alcove with be a 48" TV center and to the right a small pantry for the kitchen. Every inch of the wall is going to be used. If I do it right, it will leave a 36" walkway between the stove hearth and the bar top.

Since the new wall will be non combustible does this meet the same specs? It seems to me that it would exceed those specs except that there would be no 1" are gap under and over the new wall as like you would have when just hanging the durock on the existing wall.

The followup question to this design is where to measure after the wall is complete? I assume that it is still to the combustible wall and not the new wall. So, for example, if the unprotected specs read 12" from the side of stove top to a combustible wall and the new wall is 1" away and is 4" thick then the stove could actual sit as close as 7" to the non-combustible wall and still be 12" from the combustible wall.

If this is true does this also apply to the back and top of the alcove if I also make them non-combustible with at least a 1" gap between the old wall/ceiling and the new wall/ceiling?

Actually the ceiling part would have about 1 foot of airspace between the new non-combustible alcove ceiling and the existing ceiling.

Is my thinking correct? I believe it is, but want to make sure before I start cutting and screwing. )

Attached is a picture of my starting point. The old chimney will be remove and replaced with UL103HT specs. Might even have to move it to the right a foot or two. Patch and cut, patch and cut. Yeah fun!

Thanks in advance for any feedback.

 

[Defiant]

Your plan seems A OK to me, read it quickly. Get ready for some other opinions and welcome to Hearth.

 

[fox9988]

Welcome kwa, if you fill out your signature line, it will save you a lot of questions (location).
Your C to C reasoning sounds right. What's the advantage of a new wall vs a shield? As you implied, you will probably have to meet alcove clearances, although it will only be halfway in the alcove. I've never seen double shielding specs (could be very helpful in a tight spot), probably too many different possible configuations to have UL spec.
Good luck, keep us posted.

 

[PapaDave]

Yep, first, welcome to the Hearth.
Boy, first post and you're already a troublemaker.
Someone with more knowledge than I should be along shortly to answer.
Oh, and don't forget the in process pics.

 

[kwa]

Thanks - glad to have found this place.

My reasoning for the double wall is that it seems to me it would be easier to afix the durock to the metal studs vs. hanging them on the 2x4 studs and leaving a 1" air gap all the way around. I'm sure many have done this and pulled off a very nice finish but I think it would be easier for me to make a new metal frame and create a durock alcove with no gaps or cracks inside the wooden alcove. A box within a box with air space in between. I am very conservative on the safety side and also think it would be safer. Maybe easier to tile over too. I guess I'll see when I get there.

I had visions of radiating waves of heat coming off my new wood stove and need to protect more than expected so I can sleep well at night. All these clearances are there for a reason right? Then of course I see the NC 30 video with the guy sticking his hands all around his stove complaining that he can't get any heat out of it and I think to myself "Maybe my plans are overkill" LOL. Even so, I'd rather be safe than sorry.

I must back track a bit. My first brick house 25 years ago did have a wood insert and blower inside a brick fireplace. It was there when I bought the house. I did not use it often but when I did it was just to toss in a few logs, watch the flames, and drink some wine. I never put much thought into it at the time and did not own the house but a couple years. I never really used it for heating. More for entertainment on a cold day.

Now there seems to be an entire science behind getting a good secondary burn, overnight burn, 24x7 heat, etc. Being in computer science the past 20 years I find the tweaking for perfection attractive. Of course a week ago when I decided to roll the old fireplace out into the front yard I was just thinking "I'll build a hearth and throw in a wood stove".

Ooops, should have done my research first. Seems to be a whole new game now and many minimal requirements that need to be met. And the technology is far more than just an iron box with a flue pipe sticking out the top.

NOW this a real project for me and not just a quick weekend fix. Huh huh huh huh huh. (My best Tim Allen)

As with any building project you have to start with a good foundation so here I am.....

 

[BrotherBart]

Pay lots of attention to clearance to combustibles. That dude on youtube tries to put his hand near my 30 when it is cranking and he looses his fingerprints. And that bushy beard of his.

Welcome to the forum. Lots of solid experience and advice here. And a friendly bunch giving same.

 

[fox9988]

Pay no attention to the nc-30 vid, or take it as what not to do. I'm sure many here will tell you, 1000 stove top temps ( do not attempt= meltdown) would be easy with Properly seasoned wood. Secondary burn, overnight burn, and 24-7 heating should be easy with the properly sized stove (unless your heating a small area). Tell us more about your set up; sqft, 1-2 story, lots of windows, open floor plan, drafty/tight, well/poorly insulated, primary/secondary heat, etc.
I noticed you asked about the BK Sirocco on another thread, it needs a 48" Wide x 72" tall alcove.

 

[kwa]

The home is a small, one story, double-wide manufactured home on a permanent crawl space foundation. I bought it because it is across the road from the log cabin my Dad and I built years ago. My brother lives on the other lot left of the cabin. Now for 20+ acres family is all we can see. The privacy was a nice plus.

It is 1000 sq feet and is of average insulation for a 15 year old home of this type.

I have already upgraded to new double-pain vinyl windows in the kitchen and will eventually make it around the entire house. I am also re-insulating the exterior walls as I remodel. Even so, it seems to be a somewhat tight space. I have not noticed any drafts of any kind. I have also added a new storm door over the new back door. I will do the same when I replace the front door. I think the weakest link is the ceiling. It has a new roof but the insulation in between the scissor trusses is not that great. I think this is my biggest loss for heating or cooling.

The interior walls are 7 feet at the exterior and rise to about 9 feet in the center. This is true for the length of the house. On a hot day the house stays cool with the AC but when I turn on the ceiling fan I can feel a wall of hot air being pulled down from the higher ceiling.

Speaking of ceiling fan there is one located right in front of where the new stove is to be installed. it would be very easy to set this on low to move the air around a bit while the stove is running. Because of the size of the space and the fans already in place I probably don't even need a blower on the stove. That's just an assumption at this point as I have yet to pick the stove.

The stove will pretty much be in the center of the house. Think rectangle with a bedroom on each end and the living room and kitchen in the middle. The stove will sit in the living room right next to the kitchen to the right. Living room and kitchen area are open to each other and gives a much larger feel for space.

Right now this is a weekend place, but in the future who knows. If the zombies attack I might bug out to the country full time or even retire out here. I won't need the city McMansion in a few years and look forward to getting the wife out here full time.

My only space limitation right now for the alcove is about 5 feet max width from side to side and about 6 feet hearth to alcove ceiling. I could probably squeak out a couple more inches in any direction but am trying to use the remaining space for other things. I also have 3 feet in front of the 2 foot alcove to build the hearth.

For the stove I think I want:

1. Something I can regulate for overnight heat but not necessarily burn 24x7. 24x7 only comes into play for weekends, if I am out of gas, or major power failure.
2. I also don't want to be run out of the place when I load up for an overnight burn or while just watching TV.
3. I'm thinking 2 - 2.5 foot firebox but have not made a final determination.
4. I like the idea of a flat top for stew, tea, or other warming functions. (If I have to survive out here for awhile the more options the better)
5. Wood should not be a problem. I can buy seasoned wood, but can also cut oak, beech, gum, hickory or pine if needed and season it myself over time.
6. It will be the center of the living room so appearance is important but not the overriding purpose. I need functional more than appeal but both would be a bonus.

In short, during good times the stove would be for weekend heat and ambiance and if the fecal matter hits the rotary device it could be my only source for heat and cooking.

I don't want much, I just want it all. lol

 

[fox9988]

Sirocco sounds like a nice fit for you. 20 hour burn times. It would be so easy to burn 24 hours, why not. Now that you posted the details, others will chime in.
Get your wood now. "Seasoned" wood rarely is.

 

[BrotherBart]

Put a Woodstock Keystone in there and be loving life.

 

[kwa]

I was seriously looking at the keystone but how do you feed it from the side in an alcove? Is it easier than it sounds?

From what I understand all of their stoves feed from the side only. Did I miss an option somewhere?

Maybe I have to revisit the specs again and my plans. Maybe I could pull the stove forward enough so that loading is not an issue and I don't start invading the walk space.

I've lost count on how many stoves and drawings I've worked up only to find that one thing or another made it seem like a no-go. It's certainly worth the time to look again.

 

[kwa]

Sirocco sounds like a nice fit for you. 20 hour burn times. It would be so easy to burn 24 hours, why not. Now that you posted the details, others will chime in.
Get your wood now. "Seasoned" wood rarely is.

My Dad has a butt load of wood next door that is several years old. Under a roof but open to the air. I could probably trade him a cord or two today for a less seasoned wood later. We built a big stone Rumsford fireplace in the cabin. He can burn 3 foot + logs on the vertical when he wants.

He's slowed down a bit with age and doesn't build that many fires anymore. He has told me before, "Why am I going to work all day to save 3 bucks in electricity?"

The cabin walls are over 6" inches thick of hand hewn logs. His winter heating bills might peak at $75 bucks per month. Maybe $100 if you count the LP gas. But, if the power is out or he is out of gas he has the Rumsford to fall back on. A couple logs in there and you can get the place to 80 degrees in no time. The wood walls, floor, and ceiling hold the heat too.

I don't think he'll mind if I pinch some of his wood until the new stuff cures.

 

[begreen]

The 1" gap behind the shield needs to be ventilated top and bottom in order to get the reduced clearances. This is not a big deal to implement and can be worked into most designs, just don't try to get by without it. Ventilation is a critical component of clearance reduction. +1 on the Keystone recommendation or perhaps a Buck 20?

 

[fox9988]

If you remove at least one of the side walls and leave it open up to the ceiling, it's no longer an alcove.? Then you will just have to meet standard C-C. Or just remove the right wall, Keystone (I've got one coming next week) loads on the right. Or is your pic flipped?

 

[Jags]

The 1" gap behind the shield needs to be ventilated top and bottom in order to get the reduced clearances.

Please do not gloss over this. Simply building another wall is not quite the same. It must have the ability to draw from the bottom as well. Not a big deal, but should be taken into consideration during the framing.

And welcome to the forum.

 

[kwa]

Please do not gloss over this. Simply building another wall is not quite the same. It must have the ability to draw from the bottom as well. Not a big deal, but should be taken into consideration during the framing.

And welcome to the forum.

Thanks - I guess I need to revisit my plans. My assumptions were based on all the details of how to protect a combustible wall and trying to go the opposite way. If the stove is placed next to a non-combustible wall at what point is it no longer an issue? I understand that if you have a brick wall touching wood studs it is still considered combustible. What type of walls are considered truly non-combustible? Is a 3.5 inch metal stud with 1/2 inch durock on both sides considers a non-combustible wall or just a fancy heat shield for the combustible wall behind it?

Not that I will ignore the specs, just more curious at this point than anything else. I suppose the manufactures assume most people will be placing their stove next to combustibles, I was trying to avoid that part of the build altogether by making all of the walls around the stove non-combustible to start with.

 

[Jags]

I understand what you are trying to do. Nothing wrong with it. You are building a non combustible wall with the steel and durock. Where the touchy part comes in is if the inspector considers your build a "wall" or a "shield". Two different things. Build your wall with slots to draw air from the bottom as well and you are covered no matter how it is perceived.

 

[kwa]

OK- That makes sense. Thanks

 

[begreen]

There's no problem with your intent, it just needs planning. You need to make sure that the alcove is wide enough to meet clearances from side to side including the stove width.Your design suggestion might work, but it is non-standard so one is guessing at the degree of heat-shielding. It's also more work and expense than is necessary.

Brick can be used because it is a standardized material and there are specific tables for this. It depends on how much clearance reduction you need.If you put up a brick wall on durock, then you will get a 33% clearance reduction and will lose about 7" width in the alcove. If you simply put up tile covered cement board spaced 1" off the studs, with a 1" opening top and bottom (which can be nicely disguised) then you lose about 3.5" total width of the alcove and gain a 66% clearance reduction. The construction is very simple, just create some long 3" strips of 1/2" cement board and tack them, doubled up, on the studs to create the 1" spacers. Then screw the full sheets of cement board through the spacers to the studs.You'll find most clearance tables in stove manuals will be based on an NFPA approved wall shield. A standardized wall shielding also makes it easy to please the inspecting authority and insurance companies.

https://www.hearth.com/econtent/index.php/articles/stove_wall_clear
NFPA clearance table:
https://www.hearth.com/econtent/index.php/wiki/NFPA_Wall_Clearance_Reductions/

 

[kwa]

Thanks to all for the good information.

I just placed my order for the Hearthstone Shelburne in matte black. It should arrive in a few weeks. In the mean time I will finalize my hearth/alcove plans making sure that all of the minimums are met for this stove plus a little room to spare.

I'll post some real pictures of my progress as I get further along.

Stock pic

 

[begreen]

I've always liked that model It's a beautiful stove.