44-54 Onslow Square – WestWood Liquid Technologies

44-54 Onslow Square


WestWood Wecryl System with Tile Effect

Private Residential

London Seamless Flat Roofing

Located in the borough of Kensington and Chelsea, 44-54 Onslow Square is a Grade II listed Georgian property comprising several apartments.  As part of a wider renovation project, repairs were required for one roof above a dwelling, portico roofs and a balcony that extends the length of the entire building featuring more than 100 ornate railings.


This highly-aesthetic project for a prestigious and historic London property, demanded the highest quality waterproofing system and a very skilled roofing contractor. The existing asphalt on the roofing areas and balcony had started to deteriorate and leak. This not only had to be replaced with a more robust waterproofing system, but a unique tile effect created to complement the historic architecture. Another challenge was that all work had to be carried out in the winter when the UK was experiencing some of its severest weather conditions.
The specification of a range of different PMMA resins ensured these requirements could be met and any challenges were overcome.

The installation began with the stripping back of the existing asphalt to the concrete and timber decks. The concrete substrate was completely saturated with water so had to be thoroughly dried. The Concrete primer was then installed across the prepped concrete and timber substrates to form a secure bond. PMMA was used for the waterproofing which was ideal for the winter installation. To ensure watertight junctions at the bottom of each of the complex balcony railings, Reinforced Putty was sculpted around each one. The contractor then had to leave site to allow the plasterers to install new render over the top of the recently waterproofed upstands to the building. When they returned, they applied a self-levelling wearing layer, using a notched trowel to achieve the correct coverage rate.

The next step was to create the tile effect, which due to the contours of the balcony and roofs, had to be set back by at least 50mm onto the flat surface. Working in very narrow spaces, the contractor applied a solvent-free PMMA-based wearing layer in pebble grey which would become the grout lines for the tiles. With a lot of care and attention, 6mm masking tape was then used to meticulously measure and mark out the tile pattern in sections. Once the tape was down, solvent-free PMMA-based sealer coat in grey was applied to create the look of the main tile. Only a small section at a time could be completed because the tape had to be removed before the resin cured. To complete the look, black and grey ‘Paint Chips’ were spread evenly into the resin whilst it cured. These special toppings provide an aesthetic and non-slip finish. The area around the railings was then finished with the same sealer coat in grey.