When water began leaking through one of Christ’s Hospital School’s flat roofs into one of the classrooms, the school contacted Thameside Roofing Ltd, a Langley Approved Contractor who then commissioned Langley to carry out a comprehensive survey to investigate the cause of the problem and to give a thorough report on the condition of all the school’s flat roofs.

The survey established that a synthetic membrane had been overlaid on four roofs a few years before to cure the problem, but that this had failed. Langley identified that the main cause of the problem was a poor standard of workmanship and a defective cavity tray which allowed rain water to pour into the space under this membrane, on top of the original asphalt roof.

Through extensive core sample analysis Langley’s technical experts found that the original asphalt waterproofing system was sound, which enabled an overlay solution to be specified as a long-term, cost effective and durable solution to the problem.

Keeping the original roofs had two main benefits: it was less expensive than replacing the roof entirely, and there was no disruption to pupils and staff using the rooms below.

Langley’s design also considered the fire hazards which had been identified in the survey. Roofs with a high level of fire risk, where there were junctions to aged cladding, to pitched roofs or to combustible materials were waterproofed with the Langley Liquid Roofing System.

For all other areas Langley’s Reinforced Bituminous Membrane (RBM) system was installed, incorporating self-adhesive membranes in areas close to these fire risks, in keeping with Safe2Torch guidelines. Thameside Roofing Ltd expertly applied both the Liquid and RBM systems to a very high standard on four roofs of the school.

Photography by Charlie Greaves.