The site required access to the building to be unhindered whilst the work was carried out. The confined paved area needed to remain open to use by large goods vehicles carrying out deliveries and collections as well as to members of the public who had storage there. With access being difficult the decision was made to encapsulate the existing system, which while starting to fail hadn’t led to the damage and saturation of the insulation. This meant that the required waterproofing system needed to be compatible with the current covering, be a single layer material, and come with a twenty year guarantee.

System 20SLFB is a fleece backed SBS membrane which can be either mechanically fixed or fully adhered with heat sealed laps. This membrane can be used as a flame free system and is also suitable to overlay the PVC single ply membrane in this case. Specification for this project was to clean and prepare the existing surface, release the tension in the PVC by slitting along the perimeter, overlay with a geotextile fleece layer, then install System 20SLFB, mechanically fixed, with System 10 underlay to the perimeter details fully bonded by torching. The new overlay system was successfully installed with minimum disturbance to the building occupants and time delay.