View Single Post
Old 10-03-12, 09:26 PM   #1
Geo NR Gee
Journeyman EcoRenovator
 
Join Date: Jan 2011
Location: Seattle
Posts: 326
Thanks: 109
Thanked 23 Times in 18 Posts
Default Where to insulate with 3.5" Foam Board

We have a stack of 4x8, 3.5 inch poly sheathed ridged foam board. It has the reflective material on both sides. Some ideas floating around are:

1. Put it on top of the 2x4 roof trusses in the attic?

2. Put it between the 2x4 roof trusses?

3. Install it under the house in the crawl space and fasten it to the bottom of the floor joists. We already have about 6+ inches of fiberglass insulation in there already?

4. Pull the siding off the house, (we have mostly 2x4 stud walls) and replace the siding on top of the 3.5 Foam board?

If we did number 1, would you leave some of the blown-in existing insulation in the space between material and the ceiling?

If we did number 2, would you blow the insulation back on top of the foam board?

If we did number 4, would it be better to pull the siding, pull the existing fiberglass insulation out replacing it with the foam board?

Geo NR Gee is offline   Reply With Quote