Pitched Roofs

Pitched roofs may be insulated at ceiling level or at rafter line: applying insulation at rafter line brings all the building volume within the insulation envelope. By insulating at rafter line with insulation part above and part between the rafters:

• the insulated space enclosed by the building envelope is substantially increased without altering the structural design; the additional space can be used as part of the initial design or converted for use at a later date.
• the whole of the building fabric is kept at a similar temperature, thereby reducing the risk of condensation on structural members.
• thermally induced movement is reduced because the roof structure is not subject to extremes of temperature.
• a board-insulated roof offers greatly improved resistance to wind-driven rain and fine snow.
• pipes, tanks and services in the loft space are protected from freezing temperatures.
• pipes and wiring at ceiling level are not hidden by insulation.

Warm pitched roofs may be formed with the insulation part above and part between the rafters.

Warm pitched roof constructions are not covered by any British Standard, although some guidance is contained in BS 5250, BS 5534 and BRE document ‘Thermal insulation: avoiding risks’.

The STYROFOAM™ solution for insulation pitched roofs at rafter line is ROOFMATE™ RL-X, a tongue and grooved STYROFOAM board.

Agrément Certificate 87/1836 covers the use of ROOFMATE™ RL-X in warm pitched roof construction.