Egg-shaped school has rubber ‘shell’

A rubber membrane has been used to provide the ‘shell’ for an egg-shaped primary school in Birmingham.

The membrane, just 1.2mm thick, is made from EPDM and covers the 1,600 sq. m Four Dwellings Primary School.

AAC Waterproofing accurately measured and prefabricated the challenging, curved roof off-site at its North Wales factory and used its Prelasti prefabricated EPDM material for the membrane.

The new primary school, built on the site of the secondary school with the same name, has been designed by project architects dRMM.

AAC discussed with dRMM its Prelasti EPDM “synthetic rubber” alternative to asphalt and felt materials, and the two worked together on a basic specification for a solution using EPDM material.

The project's lead contractor Birmingham Lend Lease Partnership chose AAC’s Prelasti solution for its reported durability, low cost, environmental (BREEAM A+) and lightweight qualities that particularly suit timber-bearing structures such as Four Dwellings.

AAC supplied a prefabricated single-ply EPDM solution consisting of a vapour control sheet, 150mm flat board insulation and Prelasti cover. The stepped-length EPDM sheets were bonded off-site using vulcanising technology, which is said to make the roof more durable than adhered strips.

AAC’s Project Manager Mike Grant said: “We are finding that timber-frame structures are being used more widely as an alternative to steel because of their environmental properties.

“EPDM is the ideal waterproofing membrane for timber structures such as Four Dwellings, as it is lightweight, environmentally sound, and involves no hot works or fires, as asphalt does.”

AAC has also installed Prelasti at TV adventurer Bear Grylls’ lighthouse off the North Wales coast, and roofed Snowdon’s rebuilt mountain summit café.