Flat Roof Extension Building Regs

Sizes of joists needed for flat roof construction.

Flat roof extension building regs.

Insulating flat roof extensions. To enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including materials and their dimensions and performance properties. Moreover the costs of a flat roof extension today are typically lower than for a pitched roof. The flat roof extension is more on trend than it once was and is free of the dreaded leaks that haunted this type of structure in the past.

Warm deck the type of insulation for this is usually of a rigid type and the thickness will vary depending on the manufacturer s specifications. A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value. Take inspiration from the ideas above to create an aesthetically pleasing extension for your unique home. Flat roof this usually consists of felting which has a slight fall to allow rain water to drain off.

Flat roof types. When installing or repairing a flat roof you must adhere to building regulations. Traditionally flat roofs were constructed with cold decks where the spaces between the joists were packed with mineral wool type insulation placed above the ceiling like a. This is placed over the roof joists and an board normally external ply is laid on top.

A qualified roofing contractor will be able to advise on this but here are some of the main guidelines. To comply with part l of the building regulations flat roofs must achieve u values of 0 18 w m k or lower. U value of a flat roof. There must be a slope of 1 80.

It must provide adequate protection against the elements keeping the buildings structure and interior dry. A roof is defined in bs 6229 as a flat roof if it has a pitch of 10 degrees or less. Part h of the building regulations regarding drainage state that water should drain to one or two edges. As you may imagine there is a fair amount of weight involved here in terms of boards felt etc.

This usually consists of felting which has a slight fall to allow rain water to drain off to enable compliance with the requirements of the building regulations to be demonstrated full details of the new roof will be needed including materials and their dimensions and performance properties. Ventilation is required for these roofs. Old asbestos roofs are often replaced with flat roofs.