Warm Deck Pitched Roof Detail

There are typically two different ways to insulate a roof a warm roof and a cold roof.

Warm deck pitched roof detail.

Warm roofs have an insulation layer above the roof deck. No ventilation is required for these types. It is the most acceptable type of construction for domestic possessions and belongings as it avoids the need for aeration of the roof construction. A warm roof building will make the entire structure of the building warm in an attempt to avoid any cold bridging.

Throughout the course of the year the roof deck and all below it is kept at a temperature close to that of the inside of the building therefore the roof structure is protected from extremes of hot and cold lessening the potential for damage caused by thermal movement. The position of the insulation can be wholly above or partially between and above the rafter. Alternatively it can be positioned between the rafters or partially between and below the rafter. The roof pitch is described by the vertical rise divided by horizontal span.

Roof pitch is expressed as a ratio of the amount of the roof s vertical rise over a corresponding horizontal distance called the run pitch is written assuming a run of a foot or 12 inches so the ratio describes how much the roof rises for every foot of its run. In building construction roof pitch is a numerical measure of the steepness of a roof. Making decision about roof pitch. Warm deck roof 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.

Warm roof deck sandwich roof warm roof systems benefit from the insulation sitting above the deck. This part is well known as slope in geometry tangent function or stair construction in trigonometry. Insulating a pitched roof above the rafters is the common method chosen for new builds and re roofing existing detached buildings as it provides superior thermal performance for the building. The british standard for tilling and slating provides specific guidance about double lapped slating where calculations and recommendations for pitch and lap of slate are based on.

This video will demonstrate how to install a cure it grp waterproofing system in a warm roof build up. The insulation is tapered to provide a fall to the roof to enable water to run to the water outlets. In case of warm roofs they have an insulation above the roof deck in this way it keeps the deck warm. This enables the temperature of the structure and the deck to be kept close to the temperature of the inside of the building hence warm.

In a warm deck roof the insulation is positioned above the structural deck and no ventilation is required.