# Insulating a Pole Barn



## dakremer (Dec 8, 2009)

Alright you smart people, let's talk insulating a pole barn. Quick background - We bought a house that has an existing double wide, double deep pole barn (24'x32'). It is not insulated at all. I would like to insulate it. It's only wood and steel. No ridge vent, and no soffit vents. Trusses and Poles are 8' apart. Girts are like 20" apart - clearly no plans on insulating it when they built it.

I want to start by insulating the roof. Here is a generic sketch up model of a pole barn - only showing the top chord of the truss and the girts. Remember there is no soffit vents or ridge vents….










I have not talked to a structural engineer yet, which clearly I'd need to do before adding weight to the roof system. That being said, this is my plan (as long as I can).....

I want to attach some 2×6 or 1×6 to the bottom of the girts, between the top chord of the trusses…..










Then add R-19 insulation between those 2×6 (or 1×6)....










My thinking is that this would give me a "dead" air space between the insulation and the roof steel (between the girts). The air would stay cold in between the girts - This could potentially protect me from condensation on the steel.










I would also probably add some clear plastic on the warm side of the insulation to also stop moisture reaching the steel.

What are your thoughts? Is there a reason you would NOT do it this way? (as long as engineer says its okay)

Before you say it…..no, I don't want to get it spray foamed. It's too expensive for me, and I don't want to spray it directly on to the steel (in case it needs to be replaced).

I live in Iowa. R-19 is not recommended for ceilings (usually recommend R30+). However, my shop will not be continuously heated throughout the winter. Probably only once a week or so (maybe less). I just want some insulation in the ceiling so I CAN add some temporary heat so I can work out there.

I'm also trying to go with the cheapest option, because this isn't our forever home, and I don't want to put a ton of money into this pole barn.

Let me know what you think….. Thanks…...


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## dakremer (Dec 8, 2009)

bump


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## GR8HUNTER (Jun 13, 2016)

maybe you could just tack up blue board run it opposite and still use your plastic wrap :<))

just a suggestion I am no expert at all LOL


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## dakremer (Dec 8, 2009)

> maybe you could just tack up blue board run it opposite and still use your plastic wrap :<))
> 
> just a suggestion I am no expert at all LOL
> 
> - GR8HUNTER


I've thought about that - and that's definitely an option. I've been keeping my eyes open for some used foam board. New stuff is pretty expensive - I'd have to compare the cost of the wood/fiberglass insulation VS foam board….


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## GR8HUNTER (Jun 13, 2016)

> maybe you could just tack up blue board run it opposite and still use your plastic wrap :<))
> 
> just a suggestion I am no expert at all LOL
> 
> ...


yes I am in same boat as you with my shed dont want to spend 500.00 on insulation just for next guy who might rip it out LOL :<(((


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## tomsteve (Jan 23, 2015)

you mentioned," only showing the top chord of the truss and the girts." im assuming these trusses have a bottom cord. if so would there be a reason you wouldnt do the work there? 
ive built a LOT of homes. working in and crawling around in trusses gets old real quick and thats 2' OC.

it seems that even if there was an R438 in the ceiling, without the walls getting some form of insulation over the R-21 the steel siding provides it wont warm up too much.


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## dakremer (Dec 8, 2009)

> you mentioned," only showing the top chord of the truss and the girts." im assuming these trusses have a bottom cord. if so would there be a reason you wouldnt do the work there?
> ive built a LOT of homes. working in and crawling around in trusses gets old real quick and thats 2 OC.
> 
> it seems that even if there was an R438 in the ceiling, without the walls getting some form of insulation over the R-21 the steel siding provides it wont warm up too much.
> ...


It's a pole barn with trusses. The SketchUp model is just showing the top chord of the truss (to simplify it). The trusses are 8' apart, so no big deal to work in between them. I dont want to put a ceiling in the polebarn for a few reasons - one, it'll be more expensive, and two, I dont want to lose the overhead space. Most heat is lost throw the ceiling (not the walls). So the plan is to insulate the ceiling first, and add insulation to the walls later….


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## dakremer (Dec 8, 2009)

*through the ceiling


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## canadianchips (Mar 12, 2010)

dakremer your pole shed has metal roof and walls ?
You are going to be dealing with condensation when you heat the inside, this will drip. 
My suggestion is leaving an air gap between the tin and the insulation. 
WET fiberglass batts have NO insulating value !
One option of doing this is make wafer insulation panels (much like they use in log homes with exposed rafters ! )
or
Rigid styrofoam comes in 4ft sheets.
My shop in Canada I had 8ft spaced rafters on a POLE SHED.. i I used 2ft x 8ft 2" rigid styrofoam. (The same panels they use here on the putside wall of houses or concrete basements) .I used 2 layers of 2" rigid . 1 layer horizontal between 8ft space. ,2nd layer the long way to cover seams.
On the walls I suggest an insulation that has foil on one side. It attaches like a bag,and its waterproof.
Unfortunately the insulation cost more than building the walls. I limped through part of the winter with nothing (In Canada its COLD in winter, spent half the time trying to heat the building so it was warm enough to play !)
BEST of luck in your building, !
Perry


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## chrisstef (Mar 3, 2010)

Use z channel instead of 2x's and you can do 4'x8' sheets of insulation. Way less weight and a lot less work.

(I cant speak to fire code or load calcs or any of that smart people stuff)


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## dakremer (Dec 8, 2009)

> dakremer your pole shed has metal roof and walls ?
> You are going to be dealing with condensation when you heat the inside, this will drip.
> My suggestion is leaving an air gap between the tin and the insulation.
> WET fiberglass batts have NO insulating value !
> ...


So if you see the drawings up above, there will be an air gap. the girts are actually on edge (not flat like I have shown). So there'll be a 3.5" cold air gap between the steel and the insulation - I'm hoping that will be enough to stop condensation. We arent going to be at this house for a long time, so I'm trying to spend as little money as possible to insulation (while still doing it correctly, or course). 4×8 Foam sheets will be too expensive for what I want to spend, unless I can find some good used ones around. Iowa gets really cold in the winter too. I'm not planning on continuously heating it. Just heat it a few times a week (maybe). The heat source will mostly likely be a wood stove. Hoping to just get enough insulation in the roof to hold in some heat.


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## dakremer (Dec 8, 2009)

> Use z channel instead of 2x's and you can do 4'x8' sheets of insulation. Way less weight and a lot less work.
> 
> (I cant speak to fire code or load calcs or any of that smart people stuff)
> 
> - chrisstef


Using foam sheets would be ideal! Its just too expensive - I dont want to put much money into this project, which is why I was figuring out how to use fiberglass. If this was a "forever shop" - I'd be spray foaming it…


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## firefighterontheside (Apr 26, 2013)

If I were you, I think I would just insulate the walls and staple some plastic or house wrap to the bottom cord of the trusses and be done with it. Minimal cost and with not having to heat the truss space it should warm up fine with a wood stove.


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## dakremer (Dec 8, 2009)

> If I were you, I think I would just insulate the walls and staple some plastic or house wrap to the bottom cord of the trusses and be done with it. Minimal cost and with not having to heat the truss space it should warm up fine with a wood stove.
> 
> - firefighterontheside


 I think that would cause condensation issues on the steel


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## tomsteve (Jan 23, 2015)

> I think that would cause condensation issues on the steel
> 
> - dakremer


you wouldnt have an airgap like you say you would on the ceiling?


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## tomsteve (Jan 23, 2015)

.


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## Snipes (Apr 3, 2012)

Dak, what your proposing will definitely work. However i'm not convinced it would be a whole lot cheaper than 4×8 foam, materials sure but how about labor to install (and you wouldn't have the itch for week).. If your trying to get by with minimum you could get by with 1".
My other thought is that even though you may not be here for long, I think you could make the proper improvements and recover when you sell very easily.


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## dakremer (Dec 8, 2009)

> Dak, what your proposing will definitely work. However i m not convinced it would be a whole lot cheaper than 4×8 foam, materials sure but how about labor to install (and you wouldn t have the itch for week).. If your trying to get by with minimum you could get by with 1".
> My other thought is that even though you may not be here for long, I think you could make the proper improvements and recover when you sell very easily.
> 
> - Snipes


I'm considering my time free, so I wont add that to the actual cost. I guess my thoughts are that the more insulation (R value) the better, in terms of stopping condensation. I want that steel to stay cold in the winter. I think the 3.5" cold air gap between the girts will help a lot. I'm not sure 1" of foam will be enough R value to hold in that heat. With fiberglass, I can do a R-19 fairly cheap, compared to getting the same R-value with 4×8 foam.

Like I said previously, I will not be heating the garage/shop continuously. Probably less than 15 days all winter. Maybe I dont need as much R-value as I think? I want to make sure I can hold in some heat, and also not cause a ton of condensation….


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## dakremer (Dec 8, 2009)

> I think that would cause condensation issues on the steel
> 
> - dakremer
> 
> ...


Putting in a ceiling would probably be the best option, if I were going to heat it continuously. Less space to heat up…..could use a blown-in fiberglass, which is fairly cheap. However, its more money than I want to spend, and I'm not looking to heat the garage continuously. Also, if you put a ceiling in, I'd have to cut in some gable vents for circulation in the newly created attic


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## tomsteve (Jan 23, 2015)

after thinking about it for a bit, what ya plan may be the way to go for the ceiling/roof. if you were to frame in for a ceiling at the bottom cord of the trusses, i think youd want to use 2 by 6 between them all which all materials just to frame would be $300+( thats 2 by 6 and using hangers). going that way you describe is basically adding rafters which will need to be at least 14'( not sure of the roof pitch. that would be roughly $200 and might be able to lessen that if ya have a saw mill nearby where you could get roughsawn stock( doesnt seem this would be something requiring the lumber stamps and all that as its really not structural).
however, i still think all of the square footage of metal siding is going to hinder heating the space up. all that steel is a LOT of area of heat sink thats going to be sucking heat out constantly.

cant hurt to do it then see how it works. you might want to add a couple ceiling fans up top to pull the warm air back down.


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## dakremer (Dec 8, 2009)

> after thinking about it for a bit, what ya plan may be the way to go for the ceiling/roof. if you were to frame in for a ceiling at the bottom cord of the trusses, i think youd want to use 2 by 6 between them all which all materials just to frame would be $300+( thats 2 by 6 and using hangers). going that way you describe is basically adding rafters which will need to be at least 14 ( not sure of the roof pitch. that would be roughly $200 and might be able to lessen that if ya have a saw mill nearby where you could get roughsawn stock( doesnt seem this would be something requiring the lumber stamps and all that as its really not structural).
> however, i still think all of the square footage of metal siding is going to hinder heating the space up. all that steel is a LOT of area of heat sink thats going to be sucking heat out constantly.
> 
> cant hurt to do it then see how it works. you might want to add a couple ceiling fans up top to pull the warm air back down.
> ...


Hopefully the R19 will be enough to keep most of the heat off the steal. I'm counting on that 3.5" air gap, between the girts, to keep the steel cool, but also add some R Value. Eventually I'll add insulation to the walls as well. Figured the roof is most important.


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## dakremer (Dec 8, 2009)

They probably don't even need to be 2×6 since its not structural - they're just something for the insulation to staple to. Would 1×6 work? or even metal studs?


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## tomsteve (Jan 23, 2015)

i would think you could use the 1 by 6 but getting them mounted could be tricky.maybe pocket holes? as for the metal studs i think you could but stapling the insulation to them wouldnt be very easy.
i think the wood wood be less expensive,too. dont know if you could get metal studs in 14' lengths but 1 by 6 construction lumber usually can be had that long,too. im thinkin it would be easier with full length material,too.


> They probably don t even need to be 2×6 since its not structural - they re just something for the insulation to staple to. Would 1×6 work? or even metal studs?
> 
> - dakremer


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