Cold Flat Roof Construction Detail

Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls.

Cold flat roof construction detail.

Hot tar and gravel. Warm cold and inverted. Flat roof design guide. Warm roof build ups can be installed on most modern construction material types such as concrete timber and timber based sheets.

There must be an adequate void minimum 50mm between the deck and the insulation traditionally mineral wool to allow free movement of air and to prevent moisture vapour being transmitted from the building outwards where it could condensate in the roof. The membrane is then attached to the insulation. There are three recognised designs of flat roof construction. In a cold roof construction the sarnafil membrane is installed directly to the structural decking usually timber with firrings to fall.

In case of warm roofs they have an insulation above the roof deck in this way it keeps the deck warm. In the case of cold. No ventilation is required for these types of roofs. A flat roof must be strong durable and stable throughout its lifetime.

Cold bridging through the system is easier to eliminate or control as ordinarily there are no breaches from the structural supports as there is in a cold roof construction. There are several methods and materials for the design of the exterior surface of a warm or cold flat roof. The 3 most common materials used for flat roof construction. 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.

Cold deck roof a cold deck roof is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof. Flat roof types. 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. It is usually the most acceptable type of construction for domestic possessions and belongings as it avoids the need for aeration of the roof construction.

Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading. It must provide adequate protection against the elements keeping the buildings structure and interior dry.