Roof Insulation Boards Between Rafters

For a ventilated roof fix battens on the inside of the rafters 50mm from the underlay to leave vented air spaces.

Roof insulation boards between rafters.

Easiest insulation for layperson to install fairly inexpensive r value doesn t fluctuate as with loose fill. Quinn therm qr roof insulation boards are recommended for installing insulation above and between the rafters given the excellent thermal properties combined with the lightweight and easy to cut and install features of these rigid pir insulation boards. Insulating the rafter space will give you a warm loft. 2 measure and cut the foam boards as.

The rafters are joined together by a horizontal ridge board at the top and tied together by ceiling joists at the bottom. Measure the space between the rafters where the insulation. Once up at roof level the between rafter boards can be cut accurately to fit the rafter spacings. Being lightweight they do not impose significant additional loads on existing structures.

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. For a new build or if a detached dwelling is being re roofed then there is scope to choose the build up of roof that suits your purposes best however if the roof insulation is being added to an existing roof for example as part of a loft. Install underlay above the rafters. R value for fiberglass or wool batts per inch is between r3 and r3 5.

Rigid polyisocyanurate pir foam insulation boards from celotex are among the most thermally efficient commonly available insulation materials on the market. A cold roof is where the insulation is between and below the rafters and the rafters remain cold. Time to get the insulation finished and get this place warm. For an un ventilated roof construction a vapour open underlay or breather.

Rolls are usually used for long expanses such as length of floor for entire attic while batts are fit between studs in attic rafters. Check out our how to video at the link below. Having chosen to insulate your rafters and potentially use the loft space as an extension of your living area you need to be aware of some safety features before you read on. 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 sarking membrane.