Flat Roof Insulation Details

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.

Flat roof insulation details.

It depends on where the insulation is installed. Flat roof insulation installation. How much ventilation does a flat roof need. Flat roofs are a less common sight in the uk owing to their typically higher maintenance requirements when compared to other forms of roof construction although they can be a versatile form of roof construction.

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. Rockwool products are available with a bitumen or mineral coated fiberglass face to be used in a number of roofing solutions. It should be of the maximum available thickness. A cold roof or hot roof.

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. The rigid foam board insulation we used was 2 thick and came in 4 x 8 sheets. No ventilation is required for these types of roofs. A warm deck roof is where the insulation is placed on top of the rafters joists and the roof covering is then placed over the insulation.

Any type of roof from tpo to epdm can be either hot or cold. A flat roof usually consists of the following. 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. Cold roofs have insulation beneath the roof deck which is beneath the roofing material.

From there the flat roof system you choose will determine the materials you apply. 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. Hot roofs have the roof deck then insulation then the roofing material. 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.

The typical u value of an existing uninsulated flat roof is 1 5w m2k.