insulation

[leveled]

I did 24 inches of green fiber on the top of my metal liner panel mounted to the bottom of the trusses, I also studded my walls and did r-19 fiberglass. No reason for spray foam in this situation kinda overkill good stuff though.

 

[Nelstomlinson]

I live in Alaska, so I have thought a lot about insulation. Fiberglass is not an insulation, but an air filter. I have remodeled houses and pulled out fiberglass batts which were dusty all the way through, because they had had convection cells in them during the winter, drawing dust through and drawing heat out. I recommend foam. Spray in is best, but the blue foam is good if you can seal it.

You need to have considerable separation between the underside of the roof and the top of the roof insulation. That pretty much requires a ceiling. Anything less is going to mean icicles and a leaky roof. The only way I would use spray foam on the underside of a roof would be on a Quonset hut, where there are no eaves for ice dams to form on. I gather that's not what you have. Your metal roof will have condensation underneath, so use foam above your ceiling, and lots of ventilation between top of insulation and bottom of roof.

On the house I am building in Interior Alaska, I used ICFs with extra foam on the outside, 8" of spray foam in the ceiling, and have about 20" minimum gap between the top of the insulation and the bottom of the roof deck.

 

[boggen]

seams were metal comes together (overlaps each other), holes at bottom of the walls, were walls meet roof, getting these places sealed up, so mice and other rodents do not get in, along with getting a seal proof from wind itself.

hard board insulation, plus spray foam, plus metal / foil insulation tape, can add up pretty quickly.

higher R value in ceiling vs walls, but making sure ya get all the cracks filled in and keep wind blowing in can be a big issue as well.

you may be limited to what you can use, when it comes to local building codes. some stuff may require an actual inside covering of some sort. while other full spray on coverings may not.

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i do like the double sided foil hard board insulation. acts kinda like a radiant barrier to reflect heat back into building (during winter) and reflect heat out of shed during summer.

if you can afford it get highest R value you can. it makes a huge difference. with a pole barn, and having a gable ceiling, your roof is going to need get up there in R value. along with say some ceiling fans or blowers to move air around.

 

[LD1]

Lots suggesting sprayfoam. If you have deep pockets go for it. But for a polebarn I really don't think the cost is worth the benifit.

 

[jack707]

Spray foam is nice my house walls are all foamed up to the studs.Your right to much money for a pole barn One guy said I had a gable roof no regular roof with a 4 1/4 pitch.

 

[yanmars]

Spray foam is nice my house walls are all foamed up to the studs.Your right to much money for a pole barn One guy said I had a gable roof no regular roof with a 4 1/4 pitch.

Now I am not saying this would work for you but here is what I did. I have a 40x81 pole barn that I did not insulate when I bought it. It had enough condensation that it "rained" inside on occasion. I was fortunate to find enough used/offal rigid foam insulation that I insulated all the sidewalls an inch thick and the ceiling at about 3 inches for as I recall around $400 plus the hardware to attach it.
I have had no condensation problems since unless it is all above the insulation and I am unaware of it. If I had deep pockets I would have had spray foam but the cost estimate was many times what I had involved. Keep in mind also that I had a fair amount of labor involved but I enjoyed that.
Just what I did, not saying it is what you would want or need.
When I say the ceiling I mean underneath the entire roof, I do not have a ceiling that is horizontal like in a house.