Adding Foam Board To Inside Of Attic Space

Earlier this year i got a question about a home that had spray foam insulation in the attic.

Adding foam board to inside of attic space.

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. A local company is saying that i need 19 inches for an r50 rating. Step 3 place caulking and furring strips. Normally in occupied areas all spray foam must be covered by a 15 minute thermal barrier such as thick drywall per code requirements in irc section 316 4 and ibc section 2603 4.

Intumescent coatings are not always needed to coat spray foam in the attic in order to meet code thermal barrier requirements. Due to cost considerations i looked at an additional five inches for a total of 12 inches and a r30 rating. To attach the insulation you can use screws with large washers a special adhesive made for adhering foam board insulation or for smaller pieces you can seal them in with caulk or spray foam. 2 measure and cut the foam boards as.

Remove any existing pieces of insulation that might have been covering the attic walls until now. Installing foam insulation board in an attic. There are seven inches of foam insulation in the attic with an r14 rating. Step 4 cut foam boards.

Select rigid foam insulation boards that are at least 1 2 inch less in thickness than the rafter space is deep if you plan to finish the attic as living space. Foam board insulation is easy to cut with a circular saw with a masonry blade or scored with a utility knife and snapped like you would drywall. Nothing unusual about that. The superattic system from dr.

Step 2 install insulation boards. After electrical rough in the backs of the boxes are sealed with low expansion gun foam insulation batts installed recycled blue jean never fiberglass foam board seams are taped and all edges sealed with gun foam including around the electrical boxes it s actually easier to do this if oversized openings are cut in the foam board leaving a gap to fill with spray foam.