# Insulating a log cabin



## zanp (Dec 10, 2008)

I have a log cabin in North Carolina that was built in 1980.  It has 6-inch thick walls (curved on outside, square on inside).  We are currently heating the house with our Regency I3100 insert located in a stone fireplace on an exterior wall of the cabin.  The stove works great when the temperature is above 35 outside.  When it is below 35 outside, we have trouble getting the house above 62 or 64. 

Anyways, I would like to improve the insulation in the cabin and my wife would like to add drywall to the interior side of the exterior walls (she wants to brighten it up a bit).  I was curious if anyone out there has ever installed drywall in a log cabin.  I was thinking of adding a 1-2" rigid insulation foam between the logs and drywall.  If I did this, would I need to install a vapor barrier?  If so, would I install the vapor barrier between the foam and logs or foam and drywall?  

The cabin sits on a basement with concrete floors and cinderblock walls (3 of the 4 walls are partially underground) .  The basement is consistently 40 degrees in the winter time.  The basement ceiling has fiberglass batt insulation that is somewhat poorly installed.  We plan to convert some the basement to living space so I plan to insulate the walls instead of trying to repair the basement ceiling insulation.  

Any thoughts on this would be greatly appreciated.


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## Frxdy (Dec 10, 2008)

Go for it... I know of no other way. I'd either have no vapor barrier.... the foam is pretty much one.... or I'd put it between sheetrock & foam.  If possible, insulate the basement walls on the outside, or just "gently" on the inside. You don't want the earth to freeze against the wall and push it inward.


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## zanp (Dec 10, 2008)

"or just “gently” on the inside. You don’t want the earth to freeze against the wall and push it inward"

Would this be a concern in NC where our temperatures are not as extreme as up north.  We do go below freezing quite a bit but it is usually not below freezing for more than a 24 hour period.  I would likely be insulating the interior walls of my basement (much easier).


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## Adios Pantalones (Dec 10, 2008)

Are the walls chinked?  If they aren't- then backer rod and caulking type chinking outside will go pretty far to seal up drafts- get a chinking in a color close to your finish and it looks good.  (Log Builder is a name that comes to mind).  Look at leaks around window sills as well.  I have round logs inside and went around stuffing backer rod into cracks- it made an amazing difference in drafts.

Look at attic insulation as well- it's easy and goes further than most other steps for heating a home.


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## zanp (Dec 10, 2008)

There is no attic.  We have cathedral ceiling with a tin roof.  I had someone come over with an IR camera and the roof insulation seems pretty good with the exception of a few small locations.  Also, when it rains you can't really hear it on the roof hopefully meaning there is decent insulation. Adding insulation to the roof would be difficult and costly I think.  

There is no chinking on the logs.  They are stacked flush on top of each other with a small tongue and groove and a very thin layer of foam (pretty much negligible).  There are definitely some gaps between the logs at the interior wall. We are having a blow test done on Friday to see where air intrusion is occurring.


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## shoeboxlen (Dec 14, 2008)

i live in a log home myself and drafts are a bit of a pain. my home was built about the same time as yours the logs are also done the same. we used the canned foam insulation (good stuff brand) on the outside in gaps before we painted the logs. then on the inside I use brown silicon caulk if I feel a cold draft just run my hands across the cracks. if you are running an insert I would highly sugest a power venter for it. they are very helpful with getting the heat out of the fireplace.  I too was thinking about doing the insulation and sheet rock route in our cathedral ceiling living room area. we were planing on using foam board insulation like is installed under siding to insulate the walls as it would also help in eveing out the walls. hope this helps some.

Len


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## zanp (Dec 14, 2008)

Can you explain what a power venter is?


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## shoeboxlen (Dec 14, 2008)

its a fan under the woodtove that blows hot air fromt he stove out into the room. my name for it may be incorrect.


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## beau5278 (Dec 15, 2008)

I don't think that you'd be happy with the results if you put drywall over insulation on you walls,I think the drywall would need something sturdier to fasten it to.I would try doing like the others say and seal the logs better,if you do want to drywall,I'd put furring strips on the inside to fasten the drywall to,I would think in NC that the airspace + drywall would raise the R value considerably,if you wanted to spend the extra time and money you could still put the board insulation between the furring strips but that would mean a lot of cutting.


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## InTheRockies (Dec 15, 2008)

At least 4 Amish-owned companies design and build custom log homes in my area.  A number of them that I've seen have drywall installed in some rooms.  Truthfully, I like the the log look, but not throughout the entire house.  (It's just personal preference, but I wouldn't want every room in my house to have wood paneling, either.  I like color and brightness.)


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## zanp (Dec 15, 2008)

My wife would like some drywall in the cabin to lighten it up a bit.  She also thinks it will compliment and showcase the wood areas that we do not cover with drywall.  If it were up to me, I would probably just leave it as it is and seal up any drafty areas.  

So if we do the drywall, I need to decide if it is worth it to install an inch of foam insulation between the logs and drywall.  Since the logs are not a completely flat surface, I plan to frame out the area (with 2 x 4s placed flat (i.e., 1.5" thicness)) and use shims to make them flush.  Then hire someone to hang drywall.


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## Gooserider (Dec 15, 2008)

shoeboxlen said:
			
		

> its a fan under the woodtove that blows hot air fromt he stove out into the room. my name for it may be incorrect.



I think most of us refer to the fan in an insert or a stove as an air circulator or something along that line...  A power venter is more commonly used to refer to a fan in the attic for forced air circulation...

Gooserider


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## zanp (Dec 15, 2008)

I do have an insert fan installed.


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## awoodman (Dec 15, 2008)

I put 8'' thick 4X8 foam in my house I rebuilt double wide modular home. Added a 30X60 pole barn style add on (1/2 was gaurage space) and use 10'' thick their and stuckod the inside for thermal mass.


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## Adios Pantalones (Dec 15, 2008)

Are you guys talking about a blower?


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## beau5278 (Dec 15, 2008)

zanp said:
			
		

> My wife would like some drywall in the cabin to lighten it up a bit.  She also thinks it will compliment and showcase the wood areas that we do not cover with drywall.  If it were up to me, I would probably just leave it as it is and seal up any drafty areas.
> 
> So if we do the drywall, I need to decide if it is worth it to install an inch of foam insulation between the logs and drywall.  Since the logs are not a completely flat surface, I plan to frame out the area (with 2 x 4s placed flat (i.e., 1.5" thicness)) and use shims to make them flush.  Then hire someone to hang drywall.



If your going to use 2x4s anyway,why don't you install them the right way with a foot and header on 2ft centers,then use 3in batting in between them.It will take a lot less time and probably be about the same cost,you could DIY a room at a time by yourself and save on labor.


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## meathead (Dec 15, 2008)

sounds like a blower to me...

I agree with beau5278 re: drywall over insulation. He had a good suggestion with furring strips and like he said dead (or almost dead) air space and drywall will give you a better r value. Between chinking the gaps up good and tight and sheetrocking over some furring strips you'll probably be all set. 

If you really feel like you need to insulate and you are going to be sheetrocking inside anyway, frame up some mock walls inside your exterior walls (will cost you a few inches of floor space against exterior walls), insulate them and sheetrock over them. You'd have to extend windowsills etc. and re trim everything, but you'll be doing most of that work when you sheetrock anyway. In my opinion, this would be pretty extreme for your climate...but you'd be buttoned up tight. Also, the mock interior walls give you the opportunity to run electric along walls that you otherwise may not have the opportunity to have it in with a log cabin. Before you sheetrock, may as well add some convinient receptacle locations etc.


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## meathead (Dec 15, 2008)

beau5278 beat me to that last post - i need to learn to type faster. 

Like he said and like I was getting at in my above post - If you're going to bother framing out a wall, frame it out the right way. It is not complicated, you can do it yourself and will be happier with the end result. You are already doing 95% of the work with 2x4's in place flat against the wall and sheetrock over them - you may as well go the extra 5% and have fully framed walls with batt insulation and the opportunity to run some electric etc. should you decide to now or in the future.


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## zanp (Dec 15, 2008)

I would prefer to minimize the amount of space this will take up in the cabin.  Also, I will have to figure out the trim and transitions from the new interior wall to existing windows and doors.  If I use 2 x 4s that will add 4-inches (3.5" + drywall) to the interior side of the wall.  I would prefer 2" if possible.


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## zanp (Dec 15, 2008)

I am thinking I will do this in multiple steps.  

First of all, the cabin sits on a cinderblock wall basement with concrete floor.  One basement wall is exposed to air while 2/3s of the other basement walls are underground.  We would like to use this for living space one day so as a first step, I think I will insulate the basement walls.  The basement stays at 40F in the wintertime.  There is some batt insulation on the basement ceiling but I think we still lose heat upstairs to our cold basement.  If I insulate the basement walls, I can run the old Fisher Mama Bear stove that is in the basement on those really cold days (20F in the NC mtns).  If I do that now, I simply heat up my cold basement walls and I can get the basement up to 50 - 55.  

In addition to insulating the basement, I will fill in the drafty spots upstairs.  

After this, I can evaluate if I need to insulate my exterior log walls on the interior side in which case I will frame out the wall properly and give up my 4".  I imagine I will not have to do this.


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## beau5278 (Dec 15, 2008)

That would probably be a smarter first step,if you insulate the basement and run a woodburner down there,you'll be surprised how much difference that makes.If the stove is big enough to heat the basement pretty good,I'd pull the insulation out of the floor and let it heat the upstairs floors also or if it only heats part of the basement,leave the insulation and put a couple of registers in to get more heat upstairs.If you decide to insulate and drywall upstairs,no matter how you do it,you'll need extension jambs for the doors and windows,on a full width log wall,there should already be extension jambs that you could pull out and make new ones that are the right width.I wasn't thinking when I said 2x4s before,your not supporting anything so you could go with 2x3s,they'd be cheaper anyway and would give you about 1in less width than 2x4 but they're going to compress the batting some.


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## zanp (Dec 15, 2008)

Is anyone familiar with this InsulPINK product?  It is designed for basements.  It is installed directly against the basement wall and secured with 1x3 furring strips.  Drywall is then attached to the furring strips.  I am curious if this would work in my upstairs area against the logs.  As I stated earlier, I will do the basement first and then I might not need any insulation upstairs.

http://insulation.owenscorning.com/homeowners/insulation-products/insulpink.aspx


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## meathead (Dec 15, 2008)

beau5278 said:
			
		

> I wasn't thinking when I said 2x4s before,your not supporting anything so you could go with 2x3s,they'd be cheaper anyway and would give you about 1in less width than 2x4 but they're going to compress the batting some.



To me that is a toss up. Compressing the batting removes a substantial chunk of its r value - In the OP's environment sounds like it won't even be needed, but I'd give up the extra inch of floor space for the added insulation value of uncompressed batts.


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## beau5278 (Dec 15, 2008)

zanp said:
			
		

> Is anyone familiar with this InsulPINK product?  It is designed for basements.  It is installed directly against the basement wall and secured with 1x3 furring strips.  Drywall is then attached to the furring strips.  I am curious if this would work in my upstairs area against the logs.  As I stated earlier, I will do the basement first and then I might not need any insulation upstairs.
> 
> http://insulation.owenscorning.com/homeowners/insulation-products/insulpink.aspx



The problem with anything like that is that your not going to have an even wall,if you draw the furring strips  tighter in one area than another and your not going to be able to draw them even with foam between the strips and the wall,it's going to let your wall get wavy,it would be worse than putting your drywall right against your logs and your not really going to know how bad it is until you hang the drywall,if your really lucky,it may come out ok,if not it'll look like crap.


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## awoodman (Dec 16, 2008)

You need to protect the block wall from the outside by puting foam against the wall and go from their. Stop the convection of cold from penetrating the wall.
This is why you guys are burning so much wood in these non insulated homes. 

Check out the best insulated home technique (Straw Bale) and how it works ,they have been around for over 100 yrs.
Log structures look beautiful but never will compair to the R 40-50 of a straw bale wall. I would sacrifice looks for efiency and insulate the outside of the house.

The second best insulated house is the ICF (foam concreet walls). If you stuco the interior walls you have thermal mass sheet rock has none.
If you like suporting the electric and gas companies just continue on making the same mistake with you're (non-insulated) homes............... 

But people want what they want not what they need..................


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## coolidge (Dec 16, 2008)

Frame up your walls in your basement, leave a 1.5" gap between wall and framework (  thermal break). Look around for a contractor to spray foam 2" Closed cell foam(2" will give you a vapor barrier) to all exterior walls. Dont forget the rim joist. Then cover with drywall or whatever you would like as long as it meets code. Insulating with foam board is a great idea, just remeber there will always be gaps and cracks that will allow heat to escape and condensation to occur ruining your finish work. You will see a huge difference if or when you use your wood stove in the basement.


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