Warm Roof Insulation Requirements

Building regulations and standards set the levels of thermal insulation required when carrying out building work either for new build or refurbishment projects.

Warm roof insulation requirements.

The waterproof layer is above the insulation and a vapour control layer is placed below the insulation. Warm loft insulation is used on pitched roofs where you are using the loft space as a room or for storage. Column a is for extensions where the existing dwelling s walls and roof u values are worse than 0 70 w m k in the walls and worse than 0 25 w m k in the ceiling. No ventilation is required for these types of roofs.

There are two basic categories of roof design. The roof insulation thickness will vary dependent on the required u value. Cold deck this is where the insulation is placed between the joists rafters or in between the ceiling joists in the case of a pitch roof. Installing a warm roof can be extremely straight forward and simple to do.

A warm roof has the insulation above the structural deck which is thus kept warm. Or else on the interior of the building just. Warm deck this is where the insulation is placed on top of the rafters joists and the roof covering is then placed over the insulation. You should leave the space under the roof tiles free from insulation to give adequate ventilation so that you don t get condensation or water coming through the tiles.

The insulation boards are placed in the space between the rafters in the loft and act as a protective layer against the cold outside whilst keeping the warm air inside. There are two ways to insulate a roof. Insulation material is placed on top of the roof rather than in between the ceiling and the decking. Insulation is placed in between the joists underneath the roof surface above.

Both these variants require different approaches to insulation which will be covered in this guide. How does room in roof insulation work. The insulation is installed under the roof in the slope. The below table shows the thickness of insulation required for a typical warm roof construction with insulation fitted above the rafters.

If 180mm is to be installed then 100mm board might be introduced between the rafters there has to be a minimum 25mm air gap between the insulation and the underside of the tiles or slates with an 80mm board running across the rafters. With a warm roof the usual process is to split the insulation into two layers. With a warm roof the insulation is installed on top of the existing surface rather than in between the rafters. Warm roofs offer a superior thermal performance and therefore come with a higher cost.

A thermal layer of fibreglass polystyrene or other insulating material should be inserted either above the roof decking the warm roof model which is suitable for homes or permanent residences.