Barrow's climate destroys traditional flat roof materials. The town sits on a peninsula exposed to the Irish Sea on three sides, receiving over 1,100mm of rainfall annually along with salt-laden winds that corrode fixings and degrade bitumen-based coverings. Traditional mineral felt flat roofs — the standard covering on tens of thousands of Barrow extensions, garages, and dormer cheeks — were never designed for this kind of punishment. They crack, blister, and fail within 10 to 15 years, often sooner on exposed properties around Walney and the seafront.
GRP (Glass Reinforced Polyester) solves every problem that makes other flat roof materials fail in Barrow. It's applied as a liquid resin reinforced with glass fibre matting, which cures to form a single rigid shell across the entire roof. There are no joints, no laps, no seams — literally no point where water can find a way through. Unlike felt, it doesn't crack in frost. Unlike EPDM, it doesn't rely on adhesive or tape at the edges. Unlike torch-on felt, there are no heat-welded laps that can separate over time. The finished surface is a continuous waterproof membrane from edge to edge.
Every GRP installation starts with the deck. We strip the old covering completely, inspect and replace any rotten or damaged timber, then install a new OSB3 structural deck if the existing boards aren't suitable. The deck must be clean, dry, and structurally sound — GRP is only as good as what it's stuck to. We then apply edge trims and upstand details before laying the glass fibre matting and rolling on the catalysed resin. The resin penetrates the matting, bonds to itself at every overlap, and cures to form a rigid waterproof shell. We finish with a topcoat in your choice of colour — typically grey, but other colours are available.
GRP is uniquely suited to Barrow's coastal environment. The cured resin is completely impervious to salt, doesn't degrade in UV light the way bitumen does, and handles thermal cycling without cracking or delaminating. It's strong enough to walk on without puncturing, which matters for maintenance access. Properties on Walney Island, along the Barrow seafront, and in exposed positions around Rampside and North Scale benefit enormously from a covering that simply doesn't care how harsh the weather gets. We've installed GRP roofs across Barrow that look exactly as they did on day one after 15 or more years of coastal exposure.
We install GRP fibreglass systems from two leading UK manufacturers — Polyroof and Topseal. Both produce high-quality resins, topcoats, and trim components specifically designed for the UK flat roofing market, and both back their systems with manufacturer guarantees of 25 years when installed by approved contractors. We're approved installers for both systems, which means the guarantee is backed by the manufacturer, not just by us — an important distinction that protects you long-term.
The resin system itself consists of three layers: a base coat of catalysed polyester resin, a layer of chopped strand glass fibre matting embedded into the wet resin, and a topcoat that provides UV protection and colour. The glass fibre reinforcement gives GRP its structural strength — it's the same technology used in boat hulls, which tells you everything you need to know about its waterproofing credentials. At overlaps and junctions, the matting layers overlap and the resin bonds to itself, creating continuous structural integrity rather than relying on tape or adhesive.
The deck beneath the GRP must be OSB3 (moisture-resistant oriented strand board) or marine-grade plywood. Standard chipboard — which was commonly used under felt roofs on Barrow extensions — isn't suitable because it swells when exposed to moisture during installation. We replace chipboard decks as standard and ensure the new boards are properly fixed and gapped to allow for thermal movement. Edge trims are GRP-specific profiles from the same manufacturer as the resin system, ensuring compatibility and a clean finish that sheds water properly into the guttering.
For warm roof build-ups, we install Celotex or Kingspan PIR insulation boards above the deck, with the GRP laid over a suitable substrate board on top. This creates an insulated sandwich that meets current Building Regulations and eliminates the condensation risk that cold flat roof build-ups suffer from in Barrow's damp climate. The insulation upgrade adds relatively little to the cost of the GRP installation and pays for itself in reduced heating bills within a few years.
We install GRP fibreglass flat roofs on properties across every part of Barrow-in-Furness — from terraced house extensions in Hindpool and Salthouse to detached garages in Hawcoat and Roose, from dormer cheeks on Walney bungalows to bay window tops on the Abbey Road villas. We've installed fibreglass roofs on hundreds of Barrow properties and understand exactly how the material performs in this coastal environment over the long term.
Beyond Barrow itself, our GRP installation service covers the entire Furness peninsula. Dalton-in-Furness, Askam and Kirkby-in-Furness, Ulverston, and Broughton and Millom are all within our regular working area. We also cover Grange-over-Sands and Newby Bridge. Need other roofing work in Barrow? See our flat roof repairs, chimney repairs, and guttering services for the full range.
If your felt or bitumen flat roof keeps leaking, keep getting patched, or is clearly past its best, a GRP fibreglass replacement is the last flat roof you'll ever need on that extension or garage. No more annual repair bills, no more worrying about the next heavy downpour, no more staining on the ceiling below — just a seamless waterproof surface that handles everything Barrow's weather throws at it for decades.
Call us for a free survey and quote. We'll inspect the existing roof and deck, measure up, discuss insulation options, and provide a detailed written quote covering everything — materials, labour, deck repairs, edge trims, and Building Regulations notification. No hidden extras, no surprise additions halfway through the job. Honest pricing from a Barrow roofer who installs GRP flat roofs week in, week out and stands behind every single one.
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