🏠 Flat Roof with a Smart Upgrade – Built to Perform, Designed to Last
At DSN+BD Construction, we know that a flat roof isn’t just a cap on a structure — it’s an opportunity to bring together smart detailing, robust performance, and seamless integration. In our latest flat roof upgrade, we delivered a system that ticks every box: weather protection, thermal efficiency, and a sleek, architectural finish — all without compromise.
🔧 A Smarter Flat Roof Build-Up
This project involved a full structural and thermal rework of the roof, not just a cosmetic upgrade. We approached it as a complete system, layer by layer:
✅ 18mm structural ply for a stable, resilient base
✅ A bitumen vapour control layer to prevent interstitial condensation
✅ 150mm PIR rigid insulation boards for high-performance thermal efficiency
✅ A self-adhered single-ply waterproof membrane — more on that below!
Each layer was chosen for performance, compatibility, and compliance — creating a high-spec build-up that will stand the test of time.
🌧️ Enter Sarnafil AT-18 FSA P – The Game-Changer
For the waterproofing layer, we went all-in on Sarnafil AT-18 FSA P, a self-adhered, high-performance membrane that delivers on every front. Why did we choose it?
💧 Outstanding waterproofing properties
🎯 Minimal material interfaces, reducing the risk of leaks at junctions and upstands
🪄 Clean, sleek visual finish that mimics profiled PPC aluminium cappings
💸 Cost-effective without compromising on quality
🔒 Backed by a full warranty and HomePro Ltd insurance guarantee
This system not only simplifies the construction process by eliminating complex transition joints and fixing points, it also streamlines future maintenance and enhances long-term durability. It’s waterproofing — made smarter.
🧠 Design-Led, Build-Informed
Because we approach every project as a design-led design and build team, we’re able to anticipate where performance and aesthetics must align. With this roof, the upstands and interfaces were seamlessly handled — with clean detailing and hidden transitions — so that the final result performs technically while looking beautifully minimal from the outside.
We also considered:
Proper drainage gradients to avoid standing water
Clean integration with parapets, fascias, and external wall finishes
Long-term serviceability without visual disruption
🌦️ Ready for the Elements, Designed for Everyday Life
Flat roofs must stand up to the full range of British weather — rain, heat, frost, UV, wind — and this system is built for it all. With the added assurance of warranty coverage and an insurance-backed guarantee, the client gets peace of mind along with a visually sharp and technically sound installation.
Thinking about a flat roof upgrade or building a new extension? We create flat roofing systems that look great, perform flawlessly, and last for years — thanks to smart material choices and fully integrated detailing.
📩 Get in touch to speak to our team about your next project.