Flat roofing specialists in Merrow. Rear extensions on 1930s–50s detached properties — typically added in the 1980s and 1990s — GRP fibreglass and EPDM rubber flat roof replacement and repair. elevated exposed position increases wind uplift loading on flat roof perimeters — EPDM mechanically fixed or fully bonded required. Free survey, 25-year system guarantee.
Flat roofing demand in Merrow comes primarily from rear extensions on 1930s–50s detached properties — typically added in the 1980s and 1990s. The elevated position on North Downs escarpment — more wind exposure than valley suburbs creates specific flat roofing challenges: elevated exposed position increases wind uplift loading on flat roof perimeters — EPDM mechanically fixed or fully bonded required. This affects both material specification and maintenance frequency for Merrow flat roofs.
For Merrow flat roofs, we survey the existing deck condition, drainage falls and upstand heights before specifying a replacement system. Moderate — well-drained elevated chalk/greensand geology, lower humidity than valley locations humidity is a factor in system choice — in persistently damp locations EPDM fully bonded is often preferable to GRP, which requires a drier installation environment. We advise on the right system for each property and location within Merrow.
GRP fibreglass is our primary recommendation for most Merrow flat roofs — it is seamless, long-lasting and handles the moderate — well-drained elevated chalk/greensand geology, lower humidity than valley locations humidity of the area well when correctly installed with proper drainage falls. EPDM rubber is specified where the installation environment or roof geometry makes GRP less appropriate. elevated exposed position increases wind uplift loading on flat roof perimeters — EPDM mechanically fixed or fully bonded required We design correct drainage falls into every installation — flat roofs that pond cause premature system failure regardless of material quality.
Merrow's North Downs position means summer surface temperatures on south-facing flat roof membranes are among the highest in the Guildford area — exceeding 70 degrees Celsius on dark GRP in July on exposed aspects. We use flexible sealant rather than rigid fillets at all Merrow flat roof junctions to accommodate the greater thermal cycling range that the elevated exposed position creates compared to valley suburb properties.
The flat roofs on Merrow's 1930s detached properties were typically added in the 1970s and 1980s. These deck structures are now 40-50 years old and the OSB or chipboard used in 1970s construction has a shorter moisture tolerance than modern structural OSB. We budget for partial deck replacement as a standard element on Merrow 1970s extension flat roof replacements and adjust the final cost based on what the strip reveals.
Merrow flat roofs on north-facing aspects benefit from an additional spring moss inspection — the combination of shade from mature garden trees on Bushy Hill Drive and Trodds Lane and reduced UV exposure creates moss growth conditions on flat roof surfaces that is more common here than on south-facing or open aspects. Moss on flat roofing should be removed before it obscures outlet conditions and developing surface cracks.
Merrow's elevated North Downs position gives flat roofs better drainage conditions than valley suburbs, but the more exposed aspect increases thermal cycling range — summer-to-winter temperature swings of 40+ degrees expand and contract flat roof membranes more aggressively. GRP fibreglass is our primary Merrow specification precisely because it handles thermal cycling better than traditional felt and bonds seamlessly without the expansion joints that can fail on exposed locations. Properties on Bushy Hill Drive and Epsom Road demonstrate this pattern clearly — call us for a free survey and we will advise on the specification most appropriate for your specific position within Merrow.
Merrow's North Downs position produces the widest seasonal temperature range of any Guildford suburb — the combination of elevated exposure and the chalk soil's rapid drainage creates summer conditions significantly warmer and drier than the valley, while winter frosts persist longer on the elevated ground. For Merrow flat roofs this means greater thermal cycling stress on the membrane across the year. GRP handles this well and is our primary Merrow specification — its seamless, rigid construction does not have the expansion joints that can open under thermal cycling on multi-section systems.
Merrow's 1930s and 1940s housing era means that any flat-roofed rear additions on these properties were typically added in the 1970s or 1980s — giving them a consistent age profile that we now recognise as the predominant end-of-life flat roofing stock in the suburb. Properties on Trodds Lane and the surrounding residential streets that added rear extensions in this period are now at or approaching the point where GRP or EPDM replacement is the only economic answer.
Free quote. No call-out fee. 10-year guarantee.
We assess the existing deck condition, drainage falls and upstand heights. We specify the right system for your property and location.
Full itemised quote including deck repair where needed, system installation, trim and guarantee terms.
Typically one day for a standard garage or extension roof. We carry correct materials for same or next-day installations.
25-year manufacturer guarantee on GRP and EPDM systems plus our 10-year workmanship guarantee on all labour.
“Rear extension flat roof — original felt from the late 1990s. They installed GRP with correct falls and upstands. Dry and guaranteed for 25 years.”
“Garage flat roof was ponding at the rear — falls were inadequate. They installed EPDM fully bonded with corrected falls and edge trim. Resolved completely.”
“Extension flat roof replacement — they took the time to advise on GRP vs EPDM honestly. Went with GRP, the finish is excellent.”
A standard single garage flat roof in GRP costs £1,200–£1,800 in Merrow. A double garage runs £1,800–£2,800. Extension roofs vary by area — typically £1,400–£3,000. All quotes are free and itemised.
Both are excellent long-life systems. For most Merrow properties GRP is our primary recommendation — seamless, hard-wearing and handles moderate — well-drained elevated chalk/greensand geology, lower humidity than valley locations humidity well. EPDM is specified where the installation environment makes GRP less appropriate. We advise on the right choice during a free survey.
Sometimes — patch repair is appropriate where the existing system is structurally sound but locally damaged. Where the system is original and aged throughout, full replacement is more economic over five years than ongoing repairs. elevated exposed position increases wind uplift loading on flat roof perimeters — EPDM mechanically fixed or fully bonded required We survey and advise honestly on which applies.
GRP fibreglass carries a 25-year manufacturer guarantee and typically lasts 30–40 years when correctly installed. EPDM rubber carries similar guarantees. Both significantly outlast traditional felt in Merrow's climate conditions.
Patch repair is appropriate when the deck is sound and damage is isolated. Full replacement is needed when the system is aged throughout or has been repeatedly patched. We assess and advise honestly during a free survey.
The minimum recommended fall is 1:80 (approximately 1.5 degrees). Falls below this cause ponding which dramatically reduces system life. We assess and correct drainage falls as part of every flat roof replacement in Guildford.
In some cases yes, and it can improve both aesthetics and longevity. It requires building control approval and structural assessment. We can advise on feasibility during a survey visit.
Covering Guildford and all surrounding Surrey suburbs within 15 miles — see all areas
Free survey, honest quote, 10-year guarantee. Local roofers who know Merrow.
01483 346 440