Sika Trocal’s Type S waterproofing membrane has been installed to provide a watertight finish on a complex roof system at a new-build family home, recently nominated for the Grand Designs RIBA House of the Year.
Designed by vPPR architects, the building required a unique roofing solution for its complex roof design, which featured seven pyramids and a vaulted roof light to maximise the natural light entering the property.
With exceptional long term performance in mind, vPPR specified 200m2 of Sika Trocal’s Type S mechanically fixed waterproofing membrane in light grey and slate grey. Trocal Metal was also specified to help reduce membrane overlaps and provide a neat finish around the edges.
Trocal discs were installed to ensure uniform spacing between the triangular roof sections, and careful metering was also required long the numerous edges of each pyramid, the abutments, up stands and the base of the roof.
The entire roof build-up comprised a S-Vap 500E vapour control layer, insulation, tube fixings and Trocal S waterproofing membrane. By using tube fixings to secure the insulation, cold bridges were kept to a minimum.
The installation process was complicated due to the limited loading space for materials, in addition to the hazardous weather conditions causing the vapour control layer and foil faced boards to become slippery and difficult to handle. As a result each board had to be hand lifted onto the roof before being cut to size and individually fixed.
To further complicate matters, all gutters feel at different angles. This meant each section of Trocal Metal had to be ordered and numbered to ensure it was used for the correct slope.
To ensure a slight fall for drainage, each gutter metal required fixing in a particular method. Upon completion of the pyramid base detail, the correct colour membrane was laid with matching straps and corners.
The membrane was lapped over or under depending on which face of the pyramid was being covered to ensure straight lines.
The project was completed over a period of five weeks by a specialist team of three applicators.
Welwyn Garden City,
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