Roof Insulation Board Between Rafters

Rigid polyisocyanurate pir foam insulation boards from celotex are among the most thermally efficient commonly available insulation materials on the market.

Roof insulation board between rafters.

R value for fiberglass or wool batts per inch is between r3 and r3 5. When you use solid insulation board to create a warm loft the key thing to remember is ventilation you must keep a 50mm gap between the roof and the rigid insulation board. Rolls are usually used for long expanses such as length of floor for entire attic while batts are fit between studs in attic rafters. Being lightweight they do not impose significant additional loads on existing structures.

There is nothing wrong with that method in princaple is just very tricky hard work and itchy. Best material to use is 100mm kingspan or celotex foil backed insulation board easily cut to size to fit between rafters. Measure the space between the rafters where the insulation will be placed and cut the insulation boards marginally wider than the space to ensure a friction fit upon installation. Depending on the specifics of the roof it may be possible to fully fill the rafter depth or in most cases leave a 25mm or 50mm air gap between the top face of the insulation and the.

Once up at roof level the between rafter boards can be cut accurately to fit the rafter spacings. In this blog post we will be looking at insulating pitched roofs and why putting insulation just between the rafters isn t a viable solution. In finished space insulation is placed between the rafter boards and drywall or other material is fastened to the face. 100mm based on 150mm rafters leaving 50mm air flow.

Rafter boards are fastened to the ridge board at the peak and the top plate where they join the wall. Fit the cut quinn therm qr insulation boards tightly between the rafters with the quinn therm branded side facing into the building. We would always recommend having a breathable membrane in place between the tiles and the rafters too to allow the roof to breathe. The boards creating the slope of the roof are wider than lumber used to build trusses 2x8s 2x10s and 2x12s are most common in rafters vs.