Foam Board insulation between attic joists?
Hello, First thanks for providing this site, and the Q/A forum. I spent the last week reading through all of the blogs, and think I have a much better plan for beginning to insulate/ air seal my 1930's craftsman/ cottage house.
I have the ability to get free / very cheap 4x8 foam board insulation. ( not styrofoam, either pink or blue iso board) I'm not exactly sure on the type(s) at this time.
Currently, my attic only has about 10-12 inches of blown in insulation, is not sealed and leaks air. The front half of the attic has a regular slope, and the back half is a low slope roof, so space is limited.
Please advise if this is a feasible plan:
1. remove all blown in insulation
2. Cut foam board to fit in between joists. Use spray foam to seal the foam between the joists, this will both insulate and create my air barrier for this portion of the attic.
3. Place More foam board pieces perpendicular on top of the joists.
I think with his method I can achieve 6-8 inches of foam. And any future projects (wiring, ect) in the attic will not cause me to kick around blown in insulation.
Any problems with this plan? I'm concerned I might need a fire barrier to meet code? but since it's is separated from the living area downstairs by the drywall ceiling is that sufficient?
Posted Fri, 07/29/2011 - 10:28
Edited Fri, 07/29/2011 - 10:42
Other Questions in Energy efficiency and durability