Air gap between framing and rigid foam?
#1
03-16-09, 09:49 AM
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Air gap between framing and rigid foam?
I live in NY and have a mostly below grade basement except for upper 2 ft.
The walls are poured not block. One wall appears to have drylok or paint from 20-30 years ago (its flaking away towards floor).
My plan was to glue rigid insulation directly to all perimeter walls. Then build out a 2*3 or 2*4 wood wall with drywall. No fiberglass fill, but I do not want to put furring strips on the wall as I may be running some plumbing thru the studs.
Do I need to leave an air gap between the rigid insulation and frame and do I need to apply drylok before adding rigid insulation to the walls?
Thanks
The walls are poured not block. One wall appears to have drylok or paint from 20-30 years ago (its flaking away towards floor).
My plan was to glue rigid insulation directly to all perimeter walls. Then build out a 2*3 or 2*4 wood wall with drywall. No fiberglass fill, but I do not want to put furring strips on the wall as I may be running some plumbing thru the studs.
Do I need to leave an air gap between the rigid insulation and frame and do I need to apply drylok before adding rigid insulation to the walls?
Thanks
#2
03-16-09, 10:33 AM
If I'm learning correctly;
No drylock as the concrete will need to be able to dry to the inside.
Yes, glue rigid to the concrete, but not foil faced or poly faced as it will need to be permeable enough to dry the concrete.
No gap necessary between framing and rigid, but leaving a gap is not a problem.
No fiberglass is OK, some is acceptable if you have more than one inch of rigid. You don't want the surface of the rigid to get cold enough to condense inside moist air.
I have attached a link which will explain better than I.
http://www.eere.energy.gov/buildings...s/db/35017.pdf
Bud
No drylock as the concrete will need to be able to dry to the inside.
Yes, glue rigid to the concrete, but not foil faced or poly faced as it will need to be permeable enough to dry the concrete.
No gap necessary between framing and rigid, but leaving a gap is not a problem.
No fiberglass is OK, some is acceptable if you have more than one inch of rigid. You don't want the surface of the rigid to get cold enough to condense inside moist air.
I have attached a link which will explain better than I.
http://www.eere.energy.gov/buildings...s/db/35017.pdf
Bud
#3
03-16-09, 11:28 AM
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Thanks Bud. Just wanted to be sure.
I may end up using 2" foam, as the local HD doesn't seem to carry 1".
With anything less than 2" I'd go with some unfaced fiber between the studs.
I may end up using 2" foam, as the local HD doesn't seem to carry 1".
With anything less than 2" I'd go with some unfaced fiber between the studs.
#4
03-16-09, 04:07 PM
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Can't recall who makes it, pink stuff at HD. 2" EPS foam, has notches for furring strips. No need to glue, and if you choose, you can install drywall directly on the furring strips. Furring strips are held with tapcons, powder actuated fasteners, etc. Wood never touches concrete. Works well in our climate, cool/cold winters, muggy summers. You always have the option of building another wall, but insulation is no longer an issue, or less so.
