BMI Redland and BMI Icopal team up to deliver a thief-proof roof

27 Mar 2019

BMI Redland and BMI Icopal materials were recently chosen by Vale of Glamorgan Council to re-roof an early 20th-century primary school.

Built in 1905, Cogan Primary School suffered from a roof that continually leaked despite being patched with various types of slate over the years. The roof’s deterioration was accelerated by thieves stripping lead flashings and it had the complexity of there being a 100m2 flat roof right in the centre of the school.

Paul Hynam, Consultant Building Surveyor to the project explains: “We chose BMI because it could offer us 15-year guarantees on the products; the roof slate was made from locally-sourced materials and because the pitched and flat products could work in conjunction on the details.”

Acting for Vale of Glamorgan Council, Paul’s aims for the project were for it to look like the existing roof, to not require any maintenance, and for products to be sourced locally to reduce the carbon footprint and its environmental impact. The new roof also needed to be installed quickly to reduce health and safety issues and ensure the work is completed during the school holidays, avoiding risk to the school’s pupils.

To reduce the risk of theft, the council also wanted to use a lead alternative and needed a secure interface between the flat and pitched roofs.

For the pitched roof, the solution was BMI Redland Cambrian Slate, an interlocking slate manufactured from recycled waste slate in nearby Merthyr Tydfil, a dry-fix system to cut down maintenance, and fixings on the ridge and hip system to mimic the previous roof.

Some of the details on the side abutments were leaking because there was only a secret gutter rather than a cover flashing, so cover flashings made from a lead alternative were installed under the coping, a difficult task because the coping stones were very large. In addition, standard eaves vents could not be used because there was lath, plaster, and tar between the rafters at eaves level. Installing eaves vents would have damaged the vaulted ceiling, so vent tiles were used for venting instead.

For the flat roof, BMI’s Area Technical Manager specified BMI Icopal’s Firesmart® SBS modified reinforced bitumen membranes, accredited by the Loss Prevention Certification Board (LPCB).

Where robust details were needed, the BMI specified specific installation methods, particularly where the pitched roof met the flat roof. BMI’s solution was to carry the waterproofing under the Cambrian Slate and up to the top of the eaves batten. This detail and others were monitored by the Area Technical Manager during installation.