Cold Flat Roof Construction Detail

The 3 most common materials used for flat roof construction.

Cold flat roof construction detail.

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. A flat roof must be strong durable and stable throughout its lifetime. 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. It must provide adequate protection against the elements keeping the buildings structure and interior dry.

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. In the case of cold. For that reason cold flat roof construction needs to keep in mind the need for unblocked airflow. 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.

In case of warm roofs they have an insulation above the roof deck in this way it keeps the deck warm. Joists are placed on edge spaced at 400 600mm centres supported by external and internal load bearing walls. There are three recognised designs of flat roof construction. Warm cold and inverted.

No ventilation is required for these types of roofs. Trada and approved document part a give guidance on sizes of joists for flat roofs relating to spans and loading. Warm roof build ups can be installed on most modern construction material types such as concrete timber and timber based sheets. Hot tar and gravel.

Flat roof types. 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. Flat roof design guide. 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.

The membrane is then attached to the insulation. There are several methods and materials for the design of the exterior surface of a warm or cold flat roof.