Bosham's quayside properties are some of the most atmospheric in the county — and some of the most demanding to roof correctly. The combination of conservation area restrictions, tidal moisture from Bosham Channel, and predominantly flint-built construction requires genuine specialist knowledge.
Bosham's quayside properties are some of the most atmospheric in the county — and some of the most demanding to roof correctly. The combination of conservation area restrictions, tidal moisture from Bosham Channel, and predominantly flint-built construction requires genuine specialist knowledge.
GRP fibreglass with marine-grade gelcoat is the recommended system for Bosham flat roofs. The tidal moisture and salt aerosol from Bosham Channel means EPDM is also appropriate for larger areas. Felt is completely unsuitable for quayside properties.
Flat roofing work in Bosham covers rear outbuildings and garage extensions on back-lane properties above the quayside. All flat roof work is surveyed before quoting — falls, drainage points, upstand details and any existing structural issues are assessed as part of the free survey.
Free quote — no call-out fee — Bosham and surrounding area
📞 01243 278085GRP fibreglass provides the longest lifespan and the most seamless finish; it is our default recommendation for most Bosham properties. EPDM rubber is cost-effective for larger areas and equally durable. Felt is not recommended for any Bosham property — the lifespan is too short to justify the cost, in Bosham's tidal harbour environment.
"Garage flat roof was leaking after only twelve years on the old felt. GRP conversion — not a drop since. Should have done it years ago."
"Extension flat roof done in GRP. Neat finish, no mess left. They explained every step of the process before starting."
"Had EPDM on the large back extension. Brilliant product, very professional installation. Highly recommend."
Bosham is tidal harbour village — the quayside properties are within metres of the water and the salt aerosol concentration here exceeds anything we measure elsewhere in the coverage area. For flat roofing in Bosham this means lead flashings on Bosham quayside properties oxidise visibly within 5 years without patination oil — the tidal exposure here is categorically different from harbour-adjacent properties a mile inland. The historic quayside cottages and victorian properties around the church are heritage stock requiring conservation-aware materials, while the residential streets further from the water are standard post-war and modern. Marine-spec lead work with patination oil is mandatory on all bosham harbour-edge properties — we do not offer it as optional on these sites.
GRP fibreglass with marine-grade gelcoat is the recommended system for Bosham flat roofs. The tidal moisture and salt aerosol from Bosham Channel means EPDM is also appropriate for larger areas. Felt is completely unsuitable for quayside properties.
A typical garage flat roof in Bosham costs £900–£,600. A rear extension flat roof is typically £1,800–£5,200 depending on size and system. We quote by the square metre after a free survey.
GRP fibreglass lasts 25 to 40 years in Bosham's conditions. EPDM rubber lasts 30 to 50 years. Traditional felt lasts 8 to 12 years at most in Bosham's tidal harbour environment — we do not recommend felt replacement for any Bosham property.
Yes — felt to GRP conversion is a standard job for us. We remove the existing felt and boarding, install new treated decking, apply the GRP system and finish with a UV-stable coloured gelcoat. The improvement in lifespan is significant and the upfront cost difference is recovered within a few years.
Blistering, cracking, pooling water after rain, or felt that has become soft and spongy to walk on are all signs a replacement is needed rather than a patch repair. If a felt flat roof is over 12 years old in Bosham's coastal climate and showing any of these signs, replacement with GRP or EPDM is almost always the more cost-effective long-term decision.
Replacing a flat roof like-for-like on a house extension or outbuilding is generally permitted development in Bosham. Changing the height or footprint, or work on a listed building or in a conservation area, may require consent. We advise at the survey stage.
Correct drainage is the single most important factor in flat roof longevity. All our flat roof installations include assessment of falls, outlet positioning and gutter connections before work starts. We correct any drainage deficiencies as part of the installation — a new flat roof laid to inadequate falls will fail early regardless of the material quality.
Every flat roof survey covers: the existing deck condition (whether the existing decking boards are sound or require replacement), the current falls (whether adequate drainage exists or whether tapered insulation is needed to correct the falls), the upstand heights (whether the covering can be taken up to the required minimum height at edges and abutments), and the outlet position and sizing. In Bosham, where tidal harbour quayside properties with maximum salt aerosol, we also assess whether coastal UV intensity or harbour moisture exposure affects the system recommendation. A flat roof that drains correctly and has proper upstand details lasts decades longer than one where these fundamentals were not addressed at installation.
GRP fibreglass is applied as a liquid laminate that cures to a rigid seamless surface. We apply two layers of chopped strand mat saturated with resin, followed by the coloured gelcoat finish. The entire surface is seamless — no joints to open, no laps to fail. Upstands are formed to the correct height and radius at all edges. Outlets are GRP-lined. The gelcoat provides UV protection that significantly outlasts felt surface treatment in Chichester's coastal UV environment. Installation requires temperatures above 5°C — we plan flat roof work around weather forecasts to ensure the correct curing conditions.
A standard single-car garage flat roof in GRP typically costs £900 to £1,800 in Bosham. Rear extension flat roofs up to 25m² cost £1,800 to £4,000. Larger areas of 25 to 60m² run £3,500 to £7,500. These prices include deck inspection, any necessary deck replacement, falls correction where needed, full GRP lamination and gelcoat finish. EPDM rubber costs approximately 10 to 15 per cent less than GRP on the same area with comparable performance over the long term.
Honest pricing from a local Chichester roofer. Call now or request a quote online.
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