Cold Flat Roof Design Detail

Flat roof types.

Cold flat roof design detail.

A cold roof is roof in which the thermal insulation layer is located between the ceiling joists meaning that everything above the insulation such as the rafters and any roof space will be colder than the living space below it. The major difference between the warm flat roof and the cold flat roof has to do with the air flow between the roofing timbers known as joists that help to hold up the roof. Basically there are two options to choose from when insulating a flat roof. In the case of a flat roof insulation is usually in the form of either a rigid board above the deck or a fibrous quilt immediately above the ceiling depending on the type of roof construction.

Hopefully this video will help explain the difference between cold flat roof construction and warm flat roof construction this videos show detailed drawings. Cold roof construction requires that a suitable ventilated air space exists above the insulation layer within which the air is constantly mobile being replenished by fresh incoming air whilst the air resident within the void space is being expelled via a natural vent action at another point. This arrangement allows the deck to become cold. Installing a warm roof can be extremely straight forward and simple to do.

Flat roof details and information relating to insulating a flat roof. Optimum roof assembly design to enclose pool. Compact unvented roof assembly r value increased to r 50 in very cold climate zones to control ice damming. Warm cold and inverted.

A roof is defined in bs 6229 as a flat roof if it has a pitch of 10 degrees or less. When we talk about a warm roof vs a cold roof what we re really talking about is the insulation of the flat roof. Details both in 2d and 3d to give a clear understanding. Flat roof design guide.

In a cold weather such roofs are inherently prone to condensation which can cause material decay and deterioration. In very cold climate zones this minimum r value should be increased to r 50. It must provide adequate protection against the elements keeping the buildings structure and interior dry. In cold climate zones the minimum total r value for the entire unvented roof assembly should be r 40.

There are three recognised designs of flat roof construction. Cold roof designing buildings wiki share your construction industry knowledge. A flat roof must be strong durable and stable throughout its lifetime. There are design differences for each type.

The building regulations in the uk provide guidance on roof design.