🏠 Sarnafil Flat Roof Installation – Seamless Waterproofing Done Right

At DSN+BD Construction, we know that getting the structure right means going beyond what’s visible. Flat roofs — especially in residential extensions — require a precise balance of performance, aesthetics, and longevity. That’s why, for this recent flat roof installation, we chose a material that delivers on all fronts: Sarnafil AT-18 FSA P.

🧰 Why Sarnafil?

The roof’s now fully set and sealed with the Sarnafil AT-18 FSA P membrane — a self-adhered, high-performance product designed specifically for flat roofs and upstands. Here’s why we chose it:

• ✅ Flexible polyolefins (FPO) construction for long-term durability

• 💧 Creates a robust, flexible waterproof barrier that adapts to movement and weather changes

• 🔥 Fully welded and sealed on-site by trained installers

• 🧱 Perfect for tricky junctions and vertical elements like upstands and parapets

• 🌧️ Excellent protection against the full force of the UK’s changing weather

This material doesn’t just sit on the roof — it bonds, seals, and defends.

🔒 Protection With Peace of Mind

We don’t just install it and walk away. Your investment is backed by a full product warranty and an insurance-backed guarantee from HomePro Ltd — giving you total reassurance that your roof is protected for the long haul.

That means no stress about leaks, no worries about workmanship, and no unexpected surprises later on. Just easy, reliable, watertight peace of mind.

🛠️ Our Flat Roof Approach

This isn’t a quick fix. It’s part of a fully considered roof system — typically starting with:

• 18mm structural ply or OSB deck

• A bitumen or foil-faced vapour control layer

• High-performance PIR insulation boards

• Tapered falls and integrated drainage, where required

• And finally, the Sarnafil AT-18 FSA P membrane — fully adhered, welded, and sealed

We design the build-up to suit the use of the space beneath, energy goals, and future maintenance needs — all while keeping detailing crisp and clean.

🌦️ Designed for British Weather, Installed for Life

Whether it’s relentless rain, UV exposure, freezing conditions or expansion and contraction through the seasons, this system is built to handle it — without compromising on appearance.

Because we’re a design-led design and build company, we don’t just focus on how it works — we focus on how it looks and lives with the rest of your home.

Need a flat roof that delivers peace of mind as well as performance?
We specify, build, and warrant premium roofing systems tailored to your project — with the finish and function you expect from DSN+BD.

📩 Get in touch to talk to us about your upcoming project.