Background
Cambridge Roofers were appointed to carry out a full refurbishment of the flat roof areas at Building 900, Chesterford Research Park, Saffron Walden. The building’s flat roofs had reached the end of their serviceable life, and the client required a long-term waterproofing solution that would restore watertightness, improve thermal performance and provide a robust, warranted finish across a range of roof types and substrates.
The Challenges
The project covered several distinct roof areas, each with its own requirements. Roofs 1, 2 and 3 needed a full strip-out of the existing waterproofing back to the structural deck before a new insulated system could be installed. Roof 4 sat on a masonry substrate, meaning the existing build-up needed to be overlaid rather than fully replaced. Roof 5, a canopy roof, presented the added complexity of occupied space beneath it, meaning watertightness had to be maintained throughout the works and temporary weathering provided during strip-out and reinstatement. Achieving good thermal performance without compromising drainage falls or the available upstand heights around parapets, thresholds and abutments was a key consideration throughout.
Cambridge Roofers’ Approach
Work began with the careful strip-out of the existing waterproofing layers on Roofs 1, 2, 3 and 5, removing redundant materials and trims back to a clean structural substrate ready to receive the new build-up. On Roof 4, the existing masonry substrate was prepared to receive an overlay system rather than a full strip and replace, in line with Triflex’s requirements for that substrate type.
A tapered insulation scheme was designed and installed across the main roof areas to achieve the best practical thermal performance, targeting a design U-value of 0.18 W/m²K, while maintaining correct falls and drainage. The Triflex ProTect reinforced liquid waterproofing membrane was then applied as a fully bonded, insulated warm roof system.
All perimeters, upstands, outlets and penetrations were detailed using the Triflex ProDetail system, with primers and reinforcement used throughout to ensure a seamless, fully bonded finish at every junction. On Roof 4, the Triflex ProFloor RS wearing layer was applied as an overlay system, with the same attention given to perimeter and outlet detailing. On Roof 5, particular care was taken to protect the occupied space below and maintain watertightness at every stage, with a Triflex-compatible wearing finish applied to areas of the canopy subject to foot traffic.
The Works in Progress
Strip-Out and Substrate Preparation
The existing roof coverings were stripped back to expose the structural plywood deck, removing all redundant layers and trims to leave a clean, sound base for the new system.
Detailing and Membrane Application
Perimeter upstands and abutments were built up and detailed using the Triflex ProDetail system to ensure a fully bonded, watertight junction at every wall and threshold.
Completed Roof
The finished roof provides a fully reinforced, seamless liquid waterproofing system across the main roof area, tied into the surrounding upstands and details.
Conclusion
The refurbishment at Building 900, Chesterford Research Park was completed to a high standard across all five roof areas, each tailored to its specific substrate and site constraints. By combining full strip and replacement where needed with a targeted overlay approach on the masonry roof, and by maintaining strict watertightness on the occupied canopy roof throughout, Cambridge Roofers delivered a durable, thermally improved and fully warranted liquid applied roofing system for the client.