Flat Roofing in Swindon & Wiltshire – Installation & Repairs

A flat roof has a very shallow fall — typically between 1:80 and 1:40 — rather than a steep pitch. In Swindon and across Wiltshire, flat roofs are found on garages, rear kitchen extensions, single-storey side returns and outbuildings attached to pitched-roof houses, and on commercial buildings. The shallow angle means drainage is critical and the waterproofing membrane carries the full burden of keeping water out. Modern flat roofing materials (GRP fibreglass, EPDM rubber) are highly reliable when correctly installed. Traditional felt, by contrast, has a much shorter lifespan and is the source of most flat roof leaks we attend on older Swindon properties.

For extensions, garages and outbuildings in Swindon and Wiltshire the main practical benefits are lower construction cost compared to a pitched roof of the same footprint, faster installation, and the ability to comply with planning height restrictions on rear extensions and side returns. Modern flat roofing materials — particularly GRP fibreglass — also offer a very long service life with zero maintenance once installed. The 25-year GRP guarantee exceeds the guarantee periods on most new pitched roof tile systems. For commercial properties, a flat roof also provides accessible space for plant, ventilation equipment and solar panel installation.

We install three flat roofing systems. GRP fibreglass is our most used system on Swindon domestic properties — installed seamlessly as poured resin, guaranteed 25 years, zero maintenance. EPDM rubber is better suited to larger flat roofs over 30–40m² and irregular shapes. High-performance torch-on felt is available where budget is the primary constraint. We advise on which system is most appropriate for each specific roof and provide pricing on alternatives where relevant, so you can make an informed decision.

The lifespan of a flat roof depends on the material used. EPDM and GRP flat roofs can last up to 50 years or more with proper maintenance. Felt roofs typically last between 15 and 20 years. Regular inspections and maintenance can help extend the life of your flat roof.

On a typical Swindon garage (15–25m²) a full GRP flat roof replacement — including stripping the old felt, inspecting and repairing the deck where necessary, and installing the new GRP system — is usually completed within one day. A larger kitchen extension roof (25–50m²) typically takes one to two days. Larger commercial flat roofs or roofs requiring significant deck repair work will take longer. We provide a clear timeframe as part of every written quote and complete flat roof work in a single continuous visit wherever possible to minimise the period the deck is exposed.

Yes, flat roofs can be installed on existing properties, including extensions, garages, and even residential homes. Whether you’re building a new structure or replacing an old roof, our team can assess your property’s needs and provide tailored solutions.

Old felt flat roofs are prone to leaks — the material degrades, becomes brittle, and splits at lap joints and upstand junctions over time. This is why so many flat roofs on older Swindon properties leak. Modern systems — GRP fibreglass and EPDM rubber — do not have the same failure modes. GRP is a seamless system with no joints or laps to fail and is extremely reliable when correctly installed with adequate drainage falls. The key factors are correct installation, proper upstand detailing and working drainage. We check outlet positions and falls during every survey and advise if falls need correction as part of the replacement work.

Call 01793 230 678 (Swindon), 0800 191 0841 (Freephone) or 0117 322 6856 (Bristol), or email gwrroofers@gmail.com. We will arrange a convenient time to inspect the roof, advise on the most appropriate system and provide a free written fixed-price quote. We cover all Swindon postcodes and the whole of Wiltshire, Bristol and Bath.