Flat Roof Board FR/ALU

Consideration should be given to the recommendations of BS 4841: Part 3 and those of the Single Ply Roofing Association.

The fall on a flat roof should be constant and steep enough to ensure that rainfall does not pond.

The fire rating when tested to EN 13501-5 and BS 476 Part 3 ‘External Fire Exposure Roof Test’ will be dependent upon waterproofing system specified

The water vapour control layer should be laid with 150mm laps, which are turned up at any vertical upstand. When the insulation boards have been positioned the laps are turned over and sealed, prior to the roof finish being completed.

Xtratherm FR/ALU foil faced boards should be laid over the vapour control layer in a break bonded pattern. The long edges of the boards should be laid at right angles to the corrugations and all board joints must be fully supported by the deck. The FR/ALU insulation boards are generally secured by approved mechanical fixings.

Xtratherm FR/ALU boards are laid over the vapour control layer in a break bonded pattern and secured with approved mechanical fixings, or secured under a ballasted system.

Care should be taken to ensure that the concrete deck is graded to the correct falls, dry, clean and free from any projections or gaps.

The specification for fixing Xtratherm roof boards will vary with the location, roof height/area and topographical data. Architectural specification should be consulted.

Generally with 2400mm x 1200mm boards, a minimum of 6 fixings are adequate, located between 50mm and 150mm from all edges, additional fixings may be placed along the centre line. Additional fixings around roof perimeter may be required. 11 fixings per 2400mm x 1200mm sheet is recommended. Counter sunk washers, 50mm in diameter should be used with each fixing. However, BS 6399: Part 2 should always be consulted. During the construction process, the construction should be protected from rain penetration during breaks in the process.