Over 1,600 sqm of ageing roofing membrane on a multi-storey commercial building was continually subjected to widespread pooling of water and subsequent leaking that was threatening to aggravate tenants and contribute to further deterioration of the overall building.
Both the tower and lower deck roof areas had a bituminous membrane overlaid with styrene insulation and gravel ballast. The existing membrane had deteriorated and delaminated from the substrate, requiring complete removal before extensive topping of the substrate could be carried out to re-establish the correct falls to water outlets.
Ardex Australia recommended a two layer system of WPM116 Shelterbit Fibre Backed Base sheet and WPM185 Mineral (bituminous sheet membrane with mineral chip surface), plus vapour vents. The bituminous sheet membranes were torch welded together to form a continuous waterproof barrier and required no additional protection apart from the mineral chip surface.
WPM116 Shelterbit Fibre Backed Base Sheet is a 2.7 mm thick polyester felt-backed modified bituminous membrane incorporating a combined fibreglass/polyester reinforcement and is installed as a base layer prior to the installation of torch-on bituminous membranes. The product is designed for application to heat-sensitive substrates such as wooden decks or thermal insulation, but can also be installed as a base-layer over contaminated or new (green) concrete decks and over sound existing membranes such as rubber, PVC, bitumen, acrylic and polyurethane.
WPM 185 Mineral is a 4 mm thick combined reinforced (combined polyester/fibreglass), APP modified, bituminous torch applied membrane with a mineral slate finish. It is resistant to chemicals and atmospheric agents, resistant to puncturing and can withstand thermal shocks. The combined tower and lower deck roof areas required a total of 1,650 sqm of product to be lifted by crane to the specified areas. The contractor, M&M Waterproofing, managed the entire project.
