Insulating Attic Roof Joists

If you have a solid floor covering the roof rafters use the claw end of a hammer to pull the floor up in several locations and blow the insulation under the boards.

Insulating attic roof joists.

Look for water stains on the roof sheathing or damp or moldy spots on attic joists and existing insulation as a clue to where leaks might be. Closed cell spray polyurethane foam spf is an excellent choice for insulating attics and rim joists. However it is the most labour intensive and most expensive option. Insulating the floor and the roof this is certainly the most interesting solution when the attic is also going to be used.

Typically you will fill the insulation blower with the insulation and blow it between the attic floor joists. When you are in the attic you re usually stepping carefully on top of the floor joists looking down at the back side of the drywall ceiling. The advantage of this approach is that the heat that is generated and circulated in the floors below is not lost through the attic floor into the rooms above. Closed cell spf is an effective thermal air moisture and vapor barrier.

They have floor joists or the bottom chords of roof trusses with drywall below. Most unvented attics incorporate spray polyurethane foam spf on the underside of the roof deck and attic walls. Then blow another layer on top of the roof rafters. You ll be installing insulation on top of this drywall ceiling.