combining cellulose attic insulation with closed cell spray foam at edges
jkarch
| Posted in General Discussion on
Would it work to combine closed cell spray foam at the edges of an attic with cellulose insulation over the majority of the attic floor? I’m designing an addition to a 1950’s era home that has minimal space for insulation in the attic. We would like to keep the new fascia level with the existing one, which means that there won’t be a lot of height for insulation at the roof edges. I’d detail it with an insulation baffle at the roof edges so that the soffit vents would work. Approximately 12″ inside the inside face of the exterior wall, there’s enough depth that I could transition from the spray foam to the cellulose. Does this sound like a crazy idea?
Replies
Does not sound like a crazy idea. Spray foam can have twice the R value per inch than cellulose.
If you will have a contractor do the work, They will have to bring two sets of equipment. (so price an option to spray the whole attic)
If you plan to DIY the spray foam, it might take more of a learning curve than you have exterior walls to insulate over.
Thanks!
Not a bad idea at all. It's done pretty often. I couldn't find a good link to the technique at FHB, but it's similar to doing the rim joist. https://www.finehomebuilding.com/2007/09/01/the-best-way-to-insulate-a-rim-joist
Thank you!