Pole barn is up, insulation and moisture questions

[SMOKEEATERFF]

Just had a 30x48x12 pole barn installed, wood trusses, 2x6 girts nailed on the outside of the building, 6” slab with vapor barrier below it. I have double bubble sandwiched between the metal exterior and the wood girt boards. When I walked in yesterday I noticed condensation on the double bubble and the doors. I plan on adding spray foam and then putting up tin for an interior wall and ceiling. Will the spray foam help with condensation or make it worse? If it helps open or closed cell? I know this has probably been asked a thousand times but everyone’s build is different. I believe the ridge and soffit have been closed off with double bubble. As soon as I raised the doors the moisture was gone. I may add a heater later on for the winter (propane) and a fan for the summer. Also will have an office with a mini split.

 

[3rdgendslmech]

Just had a 30x48x12 pole barn installed, wood trusses, 2x6 gifts nailed on the outside of the building, 6” slab with vapor barrier below it. I have double bubble sandwiched between the metal exterior and the wood gift boards. When I walked in yesterday I noticed condensation on the double bubble and the doors. I plan on adding spray foam and then putting up tin for an interior wall and ceiling. Will the spray foam help with condensation or make it worse? If it helps open or closed cell? I know this has probably been asked a thousand times but everyone’s build is different. I believe the ridge and soffit have been closed off with double bubble. As soon as I raised the doors the moisture was gone. I may add a heater later on for the winter (propane) and a fan for the summer. Also will have an office with a mini split.

I could be wrong but if the soffit and ridge vents were blocked off then you're def going to have condensation, specially since the concrete was just poured. Even though the concrete looks dry and you can walk on it its still holding a good bit of moisture for days. I got finished with my building right about the middle of summer and in Md its usually pretty humid from July until early september I had no moisture at all with vented soffit and ridge.
Can you cut out the center section along the ridge so it can breath? I'm planning on putting bubble insulation up but on the bottom side of the purlins and was told to leave a little sag between the purlins so you could get air flow.

 

[SMOKEEATERFF]

I can but if I spray it then it wouldn’t help. Plus I’ll be putting up a tin ceiling. Should I put in an exhaust fan to pull air though or get some type of dehumidifier?

 

[SMOKEEATERFF]

Any body out there?

 

[Randy in Maine]

Condensation happens when warm moist air touches cold anything. Usually 3" of closed cell foam keeps that from happening. Venting (as in ridge or soffit vents) is not required using foam as there is nothing to vent.

 

[SMOKEEATERFF]

Any issues with spraying directly to the double bubble for the roof? A couple said to remove in case the roof ever leaks. They think that the water would cause the closed cell to collapse due to the water weight.

 

[timdgsr]

Any issues with spraying directly to the double bubble for the roof? A couple said to remove in case the roof ever leaks. They think that the water would cause the closed cell to collapse due to the water weight.

Did you ever come up with an answer for this?

I was curious if a radiant insulation thats between the purlins and the exterior metal needed to be removed prior to foam insulation as well. I would assume you should, but you know what they say about assumptions. Plus I'd really rather not have to cut it all out.

 

[Fibersport]

Any unvented combustion heat will add moisture so you need to reconsider your type of heat if you want it dry. Your condensation may have been caused just by a temperature drop at night, also without air movement, you will always feel humidity in the air. Can't comment on spray foam, I have no experience with it.

 

[Warrenator]

I have spray foam, closed cell, on my pole barn. I really like it but it wasn't cheap! Makes it feel as dry as a house inside, comfy cool in the summer too. The humidity level in there is fine, even in rainy Portland. I did run a dehumidifier for the first few months as the concrete cured, after a while it seemed unnecessary.

Might try a dehumidifier only just to see. You can watch and see how much water it collects, how much it runs, etc.

 

[Bigchief]

Spray foam guys will want the double bubble out of there and everything dried out before they apply the foam. The foam needs to be applied and adhered to a stable base.....and double bubble is anything but that.

An alterrnative is PolyIsoCyanate (PIC) sheets cut to fit tight between the perlins then caulk or foam any breaks and tape the seams. I put 1.5" foil faced PIC against the steel between the perlins and then put 3.5" kraft faced PIC over that and the perlins between the poles on my 30x30 pole barn. All gaps foamed in with great stuff. Its tighter than a tick....thats over R30 on the walls! Studded the walls out to meet the 6x6 poles and skinned it flush with OSB. Hope to paint the walls this weekend.

I got 30 4x8 sheets of 3.5" and 30 4x8 sheets of 1.5" from a place in Buffalo that reclaims sheets from tearoffs and also gets factory 2nds....1100 bucks delivered.

The PIC wedged and attached will tolerate the double bubble too....so no need to get rid of it.

-Mike

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[readhead]

Bubble wrap is worthless. It will fail and when it does the spray foam will fall out. It doesn't matter now but why didn't you insulate when the siding was installed? Blanket insulation can be installed at this point and probably be the most economical solution.