GRP fibreglass and EPDM flat roofing specialists in Calne — extensions, garages and outbuildings. Correct drainage, proper upstand detailing, 25-year material guarantee. Free no-obligation quotes.
Tell us the job in 30 seconds. No pushy sales, no call-out fee.
📞 Call Now: 01249 247 076In short: Flat Roofing in Calne: Flat roofing runs £900–£2,500 for a typical extension. We cover Calne and the surrounding SN11 area with free quotes, no call-out fee, and a 10-year workmanship guarantee. Failing felt flat roofs are best replaced in GRP or EPDM rather than patched.
All flat roofing work across Calne and surrounding Wiltshire — same local team, same standards, same guarantee as our Chippenham base.
Seamless, UV stable, 25-year material guarantee. Our standard recommendation for domestic extensions. Installed in one day on most standard roofs.
Get a quote →Better suited to large or complex roof shapes with significant thermal movement. 20-year material guarantee. Excellent performance on wide-span outbuildings.
Get a quote →Budget flat roofing option. Shorter lifespan than GRP or EPDM but appropriate where cost is the primary constraint. We advise honestly on expected service life.
Get a quote →Included on every flat roof replacement. We inspect boards before laying the new membrane — rotten or damaged deck is replaced as part of the same visit.
Get a quote →Ponding flat roofs have a fall problem, not just a membrane problem. We correct drainage falls as standard on every flat roof replacement — not just relay over the existing profile.
Get a quote →Sudden flat roof failure causing active water ingress. Same-day temporary seal available. Permanent GRP replacement scheduled within the week.
Get a quote →Calne's elevated chalk ridge position creates more UV and thermal cycling than valley towns — felt and lead age faster on exposed south-facing slopes. For flat roofing work in Calne, this means specification choices that reflect the actual conditions rather than generic Wiltshire averages.
1980s–90s estate housing on Studley and Quemerford drives the majority of maintenance calls. We are 6 miles east from Calne — 12 minutes — with no travel surcharge and same local knowledge that applies to every property type in this area.
Free quotes. No call-out fees. 12 minutes from Chippenham.
Failing felt flat roofs are best replaced in GRP or EPDM rather than patched in Calne. Calne mixes a stone-built market-town core with Victorian terraces off the London Road and substantial post-war and modern estates on the edges. On this kind of stock, the common problems are nail sickness on the post-war estates, slipped tiles after wind, and failing Victorian leadwork in the older core — and knowing which you are dealing with is the difference between a lasting fix and money wasted.
Flat roofing in Calne is dominated by rear extension work on the 1980s and 1990s estate housing in Studley and Quemerford. These properties were built with felt flat roofs on single-storey rear extensions — now 30–40 years old and well past their design life. We replace these with GRP fibreglass as standard: same cost bracket as re-felting, 25-year material guarantee, and genuinely watertight rather than temporarily patched.
Calne's elevated position means flat roofs on exposed elevations are subject to more UV and thermal cycling than lower Avon Valley towns. This accelerates felt degradation and increases the frequency of blistering and joint failure. GRP is particularly well-suited to Calne's exposure profile — it's UV stable, seamless once cured, and doesn't suffer the freeze-thaw cracking that affects felt on exposed north Wiltshire properties.
We remove the old covering and inspect the deck for rot — the step most quotes skip.
We check and correct drainage falls so water runs off cleanly rather than ponding.
A fixed price covering deck repairs, membrane and trims, agreed before work starts.
GRP is laid wet and cures seamless; EPDM is bonded as one sheet. Trims and upstands dressed in.
The finished roof carries a 25-year material guarantee (GRP) plus our workmanship cover.
| Job | Typical duration |
|---|---|
| Small extension (GRP, up to 15m²) | 1–2 days |
| Standard extension (GRP) | 2–3 days |
| Garage roof (EPDM) | 1 day |
| Deck / board replacement | +half to full day |
| Larger / commercial flat roof | per assessment |
GRP needs dry conditions to cure; we won't lay fibreglass in rain, so winter jobs are weather-scheduled.
Calne's town-centre streets around The Strand are tight with no side access; the outer estates have generous access for scaffold and skips. Pavement scaffold and skip permits in Calne go through Wiltshire Council; on tight streets like The Strand, Church Street, Curzon Street we allow extra time for setup and access.
Flat roofing runs £900–£2,500 for a typical extension. Calne pricing tracks Chippenham, adjusted for access on Calne's stock.
| Job | Typical range | Notes |
|---|---|---|
| GRP small extension (up to 15m²) | £1,200–£1,800 | 25-year guarantee |
| GRP standard extension (15–25m²) | £1,800–£2,500 | Seamless fibreglass |
| EPDM standard extension | £900–£1,800 | Single bonded sheet |
| Garage roof (GRP or EPDM) | £800–£1,600 | Per garage |
| Deck / board replacement | £150–£400 | Where timber has gone soft |
| Larger / commercial flat roof | from £45/m² | Single-ply or GRP |
No deposit on jobs under £500. On larger flat roofs, no payment before materials are on site. VAT included. Payment on completion once tested and dry.
Covering SN11 and surrounding postcodes.
GRP carries a 25-year material guarantee and EPDM 20 years; our workmanship cover sits on top, and the deck and falls — which decide longevity — are guaranteed too.
A day or two of work over a single room, minimal internal disruption; we clear the old felt and all waste on completion. You do not need to stay home for external work.
EPDM can go on year-round; GRP needs a dry weather window. We temporary-weatherproof if rain interrupts a job. Calne sits in the Marden valley, so low-lying properties hold damp longer and the exposed edges catch the south-westerly weather.
"Extension flat roof replaced in GRP after 30 years of felt patching. Deck inspected, boards sound, drainage corrected. Dry from the first day. Should have done it years ago."
"GRP replacement on 1985 extension — felt had been leaking for two winters. Done in a day, no mess, 25-year guarantee. Excellent."
"Large L-shaped extension flat roof in EPDM. Complex geometry handled correctly. Better than the felt it replaced by a significant margin."
GRP fibreglass up to 20m²: £1,200–£2,500. EPDM up to 20m²: £900–£1,800. Includes strip, deck inspection, drainage correction and installation. Free written quote — call 01249 247 076.
Yes — GRP is UV stable and handles Calne's thermal cycling better than felt. It's seamless once cured and doesn't suffer the joint failures that affect felt on exposed north Wiltshire properties.
Felt flat roofs have a 15–25 year design life. Repeated patching extends the surface life but doesn't address underlying membrane failure. GRP replacement is the permanent solution.
GRP installation requires temperatures above 5°C for correct curing. We schedule GRP installations around weather windows and won't apply GRP in conditions that would compromise the cure. EPDM can be installed in colder conditions.
Yes — garages and outbuildings are a significant part of our flat roofing workload. Same specification and guarantee as domestic extensions.
A standard single-storey extension flat roof takes one day to replace. Larger or more complex roofs may take two days. We give a realistic timeline in every quote.
6 miles east — 12 minutes. No travel surcharge. Free surveys and quotes throughout the Calne area.
No call-out fees. No obligation. Local roofer covering all of Wiltshire.
01249 247 076Last updated: August 2026