Earlier this year i got a question about a home that had spray foam insulation in the attic.
Vented attic spray foam insulation.
Spray foam insulation that s convenient and easy to use.
Both low density open cell and medium density closed cell spray foam can be used in an unvented attic to provide the needed thermal resistance and airtightness.
100 free of cfcs vocs penta bdes urea formaldehyde.
Use closed cell foam it green for attic rafters.
Attic ceiling to stop airborne moisture from reaching a cold surface and condensing inside the building envelope in this design insulation effectively separates the interior and exterior spaces while slowing down moisture flow so the dewpoint is not achieved within.
Nothing unusual about that.
One huge benefit of the spray foam insulated attic is that conditioned air leakage from the ac furnace duct system is contained and used to condition the attic.
Class i e 84 fire retardant meets building code spec.
Unvented attic assemblies unvented attics rely on an air impermeable insulation installed to the roof deck s underside i e.
A lot of builders and homeowners are going with spray foam insulation because of the airtightness benefits but then the questioner mentioned that the spray foam contractor had intentionally left big holes to the outside by not sealing the gable vents.
Rigid foam and spray foam are two of them.
Heat from the house rises up to the attic but when there isn t one the heat rises up to the roof.
When we seal the attic with spray foam it s as tight as a butter tub.
Unvented attics sometimes called sealed enclosed or encapsulated attics feature insulation on the underside of the roof decking rather than on the attic floor.
R value of 7 in 1 inch 97 closed cell foam.
Image courtesy of d7 spray foam insulation houston tx using spray foam insulation in an unvented attic application.
In comparison to high density spray foam medium density spray foam is applied as a low or high pressure two component polyurethane spray foam.
All insulation materials require proper venting.
The unvented attic space is considered the most effective and up to date building practice particularly by the spray foam industry.
Cathedral roofs especially need a lot more insulation between the ceiling and the rafters because there usually isn t any attic space.
However in a traditionally insulated attic insulation on the ceiling the attic is vented.
The best attic insulation.