Lawrence Hall- Westwood Liquid Technologies
Lawrence Hall, Westminster
Wecryl 230 PMMA
Kingsley Roofing (Midlands) Ltd
Lawrence Hall is a Grade II listed building which has vaulted ceilings and Art Deco interior features. It was awarded a gold medal by the Royal Institute of British Architects for it’s dramatic architecture. It was constructed between 1925 and 1928. It has been used as a filming location for various movies as well as TV dramas. Various roof levels cascade down the side of the building. The various roofs had been suffering with water ingress for a considerable amount of time. The existing asphalt and Foamglas insulation were stripped up and replaced with a new warm roof and Wecryl 230 waterproofing.
The existing Foamglas insulation was saturated and needed to be stripped up to all the roof levels. Removing the existing asphalt and warm roof construction was made furthermore difficult with the presence of a substantial amount of glazing and Georgian Wired circular roof lights.
As part of the waterproofing works a small high-level terrace area was stripped up and replaced with a new warm roof and protective cement board. On top of this were installed the waterproofing membrane with an additional trowel on wearing layer and quartz sand broadcast. A final sealer coat was then applied.
As part of the overall scheme several north lights, plant room and stair/ lift core roofs were also waterproofed.
Due to time constraints the installation of the new warm roof and waterproofing had to be co-ordinated with the strip up and removal of the existing build up at the same time.
Separate to the waterproofing of the roof areas, the client had shown a desire to address the tired and old glazing which had been prone to leaking. Replacing the windows was deemed cost prohibitive. As a robust repair, Wecryl 230 thix & fleece, as well as Weseal 815 Fibre Putty was used to waterproof around the window sills to all of the roof levels. WestWood glass primer and the self-terminating properties of Wecryl 230 thix made it possible to do so.
When removing the existing asphalt from below the window sills, a considerable amount of making good was required to the substrate. Rapid curing PMMA putty and mortar were utilised as part of the preparation, before the waterproofing membrane was applied.
The sides to the circular roof lights were relatively high, especially on the lower levels. The use of a thixotropic rapid curing resin, made it easier to waterproof these elements. The circular shape of these also made it awkward when dressing down the polyester fleece reinforcement from the sides of the roof lights to the flat areas.