A newly built bespoke garden room at a property in Ambleside needed a premium flat roof covering that would complement its contemporary design and deliver maintenance-free performance for decades. Our EPDM rubber roofing team installed a fully bonded Firestone RubberGard membrane with integrated warm roof insulation, creating a silent, durable, and visually clean flat roof.
This wasn't a repair project but a new build requirement. The homeowner in Ambleside had commissioned a bespoke garden room — a contemporary timber-framed structure with floor-to-ceiling glazing on three sides, designed as a year-round living space overlooking the fells. The architect specified a flat roof to maintain the clean, modern aesthetic, but the homeowner had experienced problems with felt and GRP on other properties and wanted the most reliable flat roof system available. Key requirements were: zero maintenance, absolute silence during rainfall (the garden room is used as a music studio), excellent thermal performance for year-round use, and a clean appearance when viewed from the bedroom windows above. After researching options, the homeowner specifically requested Firestone EPDM rubber membrane — widely regarded as the most proven and reliable flat roof system in the world.
Working with the timber frame builder, we designed a warm roof build-up starting with the structural OSB3 deck. Kingspan Therma TR26 PIR insulation boards were laid in 100mm thickness (achieving a U-value of 0.16 W/m²K — well beyond Building Regulation minimums) with tapered sections creating a 1:60 fall to the rear gutter. An 11mm OSB3 overlay board was installed on top of the insulation to provide a rigid, smooth substrate for the membrane. The Firestone RubberGard EPDM membrane (1.14mm thickness) was supplied in a single sheet cut to size in the factory, meaning the entire 24-square-metre roof was covered with one continuous piece of rubber — zero joints, zero seams. The membrane was fully bonded to the substrate using Firestone's water-based bonding adhesive, providing both adhesion and wind uplift resistance. At the perimeter, the EPDM was dressed over aluminium edge trims with a factory-formed drip detail. At the rear wall abutment, the membrane was carried 200mm up the wall and terminated under a new lead flashing. The new aluminium box gutter was installed at the rear to handle all roof drainage.
The garden room roof has performed impeccably since installation. The fully bonded single-sheet construction means there are literally no potential leak points — the entire roof is one continuous rubber membrane. The homeowner has confirmed that rainfall is completely inaudible inside the garden room, thanks to the combination of EPDM's soft rubber composition and the insulation mass beneath. The thermal performance has exceeded expectations — the garden room maintains comfortable temperatures year-round with minimal heating input. When viewed from the bedroom above, the EPDM presents a clean, uniform dark grey surface that complements the contemporary design. We provided a 20-year system guarantee backed by Firestone's manufacturer warranty on this EPDM installation.
Firestone RubberGard is the world's most proven EPDM roofing membrane, with over 1.5 billion square metres installed globally since the 1960s. The 1.14mm single-ply rubber membrane remains permanently flexible from -45°C to +130°C, never becomes brittle, and is completely resistant to UV degradation, ozone, and atmospheric pollutants. EPDM has the longest documented service life of any single-ply membrane — over 60 years in independent testing — making it the gold standard for premium flat roof applications. For this Ambleside garden room, the membrane was factory-cut to a single sheet eliminating all field joints.
At 100mm thickness, this premium PIR insulation achieves a U-value of 0.16 W/m²K — significantly exceeding current Building Regulation requirements and providing exceptional year-round thermal performance. The closed-cell foam structure prevents moisture absorption, and the foil facings provide an additional vapour barrier. The tapered sections were factory-cut to create the required 1:60 fall, eliminating on-site cutting waste.
The EPDM was fully bonded using Firestone's own water-based adhesive, which provides excellent adhesion strength while being environmentally responsible — no solvents, no VOCs, and safe to apply in enclosed spaces. Full bonding means the membrane cannot balloon or flutter in wind, providing a silent roof performance that is critical for this music studio application.
All perimeter trims were specified in powder-coated aluminium with pre-formed drip details, providing a clean, maintenance-free edge termination. The rear box gutter was fabricated in matching powder-coated aluminium with welded joints for a seamless appearance that complements the garden room's contemporary design.
From garden rooms to extensions, garages to commercial buildings, our EPDM rubber roofing team delivers premium Firestone installations throughout Ambleside and the Lake District. We also offer GRP fibreglass and felt roofing systems. Contact us for a free survey and quotation.
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