Flat Roof Insulation Details

A flat roof usually consists of the following.

Flat roof insulation details.

Cold roofs have insulation beneath the roof deck which is beneath the roofing material. How much ventilation does a flat roof need. Once the roof demo was complete and the flat roof was cleared of any remaining debris some rotted 2x material around the perimeter of the roof was replaced. The typical u value of an existing uninsulated flat roof is 1 5w m2k.

It depends on where the insulation is installed. Underneath the basics flat roofs are usually constructed with a ceiling nailed to joists which support a deck usually wood in residential construction a vapor barrier insulation and a roof board. However in many situations the insulation may need to be primarily or entirely below the flat roof membrane and between the roof joists if so what are the best options. The answer depends on the type of roof you have.

Hot roofs have the roof deck then insulation then the roofing material. Flat roofs have often been built with the insulation all on top of the vapor closed drainage plane as this avoids dew point condensation issues inboard of the roofing. Flat roof insulation thickness the chosen insulation laid on top of this should be able to take the weight of anything put above it on the roof without compression or protected from compression by further sheeting. From there the flat roof system you choose will determine the materials you apply.

A cold roof or hot roof. Rockwool stone wool roof insulation combines the thermal performance dimensional stability impact resistance and acoustic control required to increase the performance of many flat roof assemblies. Any type of roof from tpo to epdm can be either hot or cold. It should be of the maximum available thickness.

Waterproof membrane to prevent water penetrating the structure and interior of the building roof deck providing the base for the waterproof membrane and in some cases the insulation thermal insulation load bearing or primary structure usually. Rockwool products are available with a bitumen or mineral coated fiberglass face to be used in a number of roofing solutions. Flat roof insulation installation. It can be difficult to provide a very high level of thermal performance in these roof types whether you re looking to insulate at joist level for a cold roof where joist depth can be an issue or above the roof deck where overall roof height may need to be.

The rigid foam board insulation we used was 2 thick and came in 4 x 8 sheets.