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fiberglass insulation properties in wood pole building, vapor and air barriers, radiant reflecting

fiberglass insulation properties in wood pole building, vapor and air barriers, radiant reflecting

fiberglass insulation properties in wood pole building, vapor and air barriers, radiant reflecting

(OP)
Working on a design for a pole building. It will be climate controlled and need to achieve good R values. Target is R20-25 walls, R35-40 roof.

What is typically done around here is guys just pinch 6" plastic faced batts between the sheeting and wood structure but obvious that causes compression of the batts and no idea what that does to the R rating. What I am looking at doing is using a reverse PBR panel which basically makes the metal stand away from the structure about 1.5", and using a thinner batts (2-3") which will expand into this area and function better. Then following with an interior faced material. This may prove tricky to achieve minimal compression and find a good way to secure it.

I have also seen a bunch of people using this foil backed bubble wrap as a vapor/air barrier and supposed radiant reflector. The issue I see is salemen are grossly misrepresenting this bubble wrap with like R20-R50 ratings!! If that was the cause, the universe would collapse. I am not sure how to properly evaluate the function of the bubble product and if it would be a better first protection layer trapped under the sheeting?

This also brings into question the air/vapor barriers. I have heard that you do not want these barriers both against the sheeting, and exposed interior walls as it causing ventilation issues? However, these buildings rarely end up ziplock tight and more or less seem to leak a LOT more air than is designed.

Is there a way to properly evaluate the radiant reflective properties UNDER the sheeting?

What I have also considered is somehow trapping void air between layers in insulation which should help boost the R values. Lots of ways to go here.

RE: fiberglass insulation properties in wood pole building, vapor and air barriers, radiant reflecting

Go here http://www.buildingscience.com/index_html start reading. Everything you need to know is there somewhere.

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