Flat Roof Extension Building Regs

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.

Flat roof extension building regs. The steels or rsj s rolled steel joists are often built into one or both walls to give added stability to the roof structure. This is placed over the roof joists and an board normally external ply is laid on top. Flat roof 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.

A flat roof must be strong durable and stable throughout its lifetime. Building regulations for insulating a roof. Heat rises and therefore the building regulations requirements for heat loss through roofs are more stringent than those for walls. Thickness varies according to the manufacturer s specifications.

A roof is defined in bs 6229 as a flat roof if it has a pitch of 10 degrees or less. There must be a slope of 1 80. Flat roof 0 18 extensions to form conservatories the accepted definition of conservatory for building control purposes in hertfordshire is a ground level extension that is thermally separated see a. On a basic level flat roof construction comes in the form of roofing timbers or joists as they are more commonly known or steels that are laid across two uprights walls in most cases.

The limiting u value the maximise u value which cannot be exceeded required under current building regulations for the roof is 0 20w m. 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 conventional loft. A lower u value indicates better insulation properties hence u value requirements usually specify a maximum value. 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. Flat roof 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. It must provide adequate protection against the elements keeping the buildings structure and interior dry. Part h of the building regulations regarding drainage state that water should drain to one or two edges.

U value of a flat roof. When installing or repairing a flat roof you must adhere to building regulations.