Adding Foam Board Between Trusses In Attic Space

Affix rigid foam insulation to the attic side of the hatch or door.

Adding foam board between trusses in attic space.

Encapsulating the rafter or top truss chord roof framing members with spray foam will improve the energy efficiency of the attic space. I m concerned about ice dams forming along the eaves of my roof in wintertime. I would like to use some of my attic space for storage. The reason trusses shouldn t hold the weight of flooring or heavy boxes is because they are typically made from relatively small boards 2x4 s in some cases and the bottom board is already carrying a significant roof load because of the design of the angled elements.

Parts of my attic are floored. This is because the effects of thermal bridging are limited which also results in the elimination of melt lines on the roof surface in cold climates. 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. Caulk all edges gaps and joints.

If you re using the attic for living space then you need to insulate the rafters. Attic hatch or door. That s because it s easier for the contractor to spray than clean up existing insulation deal with any can lights or venting etc. Batts between rafters in would require adding ventilation between the insulation roof deck.

Consumers are often told by spray foam contractors to do the rafters. Use a zippered insulated tent to keep the enclosure draft free attic tent at 7 attic cover insulator 120. If you re going to cut n cobble get some 2 thick goods and glue in a 2x2 foam tight to the roof deck rafter as spacer rails for the vent cavity then cut the center goods at least an inch narrower than the cavity and foam it in with frothpak or other 2 part foam kit. Cut foam boards to fit snugly between the trusses.

Hack n stack sealed foam board between the rafters would be better since it s at least an air impermeable insulation but even that would require a vent gap below the roof deck to meet code and you d still be under r38 on that 2x6 rafters unless you. Pull down stair or ladder. Attics are a top pick when homeowners decide to gain some extra storage or add a guest room but not all attic flooring structures are up to the task of supporting the weight of a new living space. Add weatherstripping around the perimeter and a sweep to the door of a walk up attic.

Remove existing insulation from the area you are working on and set it to one side. My attic is framed with rafters and a ridge board not with roof trusses. Obstructions such as electrical wires will require cuts in the barrier.