GRP fibreglass, EPDM and felt flat roofing for extensions, garages and outbuildings across Canterbury and East Kent. Designed for Kent's wet conditions. Free quotes.
Flat roofing in Canterbury costs £1,200–£6,000 for GRP fibreglass or EPDM rubber systems, each with a 25-year material guarantee. Ideal for extensions, garages and dormers. We don't fit short-life felt as a replacement. Free surveys across Canterbury. Call 0122 763 4920 for a fixed-price quote.
A failing flat roof is usually ageing felt that has cracked, blistered or split at a seam or upstand. Here is how to tell whether yours needs a patch or a recover.
When it is not the answer: If a modern GRP or EPDM roof has a single localised puncture, a patch is enough — you do not need a full recover. Read the full guide.
We locate the failure and check the deck and the falls beneath the covering.
Fixed price for patch or full recover in GRP or EPDM, deck repair included if needed.
Most flat roofs are recovered in one visit; larger areas booked in.
Old covering off, deck repaired, new system laid with proper falls to the outlet.
Site cleared and the roof guaranteed.
| Job | Typical duration |
|---|---|
| Garage / small outbuilding | 1 day |
| Single-storey extension | 1–2 days |
| Dormer flat roof | 1 day |
| Large wrap-around extension | 2–3 days |
GRP needs a dry spell to cure; we schedule around the forecast and never lay onto a wet deck.
Most flat roofs are low and reached from a tower; scaffold only where the flat roof is at height or wraps a two-storey return. Scaffold is specified for: first-floor or wrap-around flat roofs, or where edge protection is needed - always itemised in your written quote, never a hidden extra, and we arrange it.
Canterbury’s medieval core and the Victorian terraces off Wincheap and St Dunstan’s often mean tight frontages, shared rear access and conservation-street constraints, so scaffold and skip placement take planning. Pavement scaffold and skip permits go through Canterbury City Council; allow a few working days on streets like Palace Street, Burgate, St Dunstan’s Street where space is tight.
GRP · EPDM · Felt · Drainage design included in all quotes
Canterbury's position in the Great Stour valley creates a microclimate that is harder on flat roofs than on pitched ones. Valley humidity is consistently higher than on surrounding high ground, which accelerates the degradation of felt membranes and creates ideal conditions for moss and algae colonisation of exposed surfaces. Drainage design is not optional in this location — it is the difference between a flat roof that lasts 30 years and one that fails in 8.
The city's extensive mature tree coverage — particularly along the Stour and in the older residential streets — creates a significant seasonal leaf load on gutters and flat roof outlets. Every flat roof we install in Canterbury is specified with outlets sized to handle autumn debris, not just normal rainfall volume.
Rear kitchen and dining extensions (the most common application in Canterbury's Victorian terraces), garage conversions and outbuildings, flat-to-pitched conversions where planning permits, dormer roof surfaces, and commercial flat roof work up to 200m². We cover all of Canterbury and East Kent from a single site visit to completion.
“Extension flat roof had been leaking for three years. Two previous companies had patched it. Canterbury Roofing stripped it, went GRP, perfect fall to the drain. No issues since installation eighteen months ago.”
“New GRP flat roof on a garage conversion. Clean job, finished in two days, looks great. They designed a proper drainage outlet and it runs dry even in heavy rain. Very pleased.”
“Had a felt roof on our rear kitchen extension that kept ponding water. Canterbury Roofing re-graded the falls, put down EPDM and it drains perfectly now. Should have done it years ago.”
| Job | Typical range | Notes |
|---|---|---|
| Garage / outbuilding | £1,200–£2,000 | EPDM or GRP |
| Single-storey extension | £2,000–£4,000 | GRP for complex shapes |
| Large / wrap-around | £3,000–£6,000 | GRP seamless |
| Dormer flat roof | £800–£2,000 | Incl. lead junctions |
| Felt strip & deck repair | from £300 | Added if deck wet |
Worked example: A 12m² rear kitchen extension off Wincheap recovered in GRP with a soft-deck patch: about £2,600.
No deposit on small flat-roof repairs. Staged payment on larger recovers, materials on site first.
Covering CT1, CT2, CT3, CT4 and surrounding postcodes.
GRP and EPDM systems carry a 10-year workmanship guarantee and 20–35 year material life — far beyond the felt we replace.
If a fault appears in covered work, we come back and put it right. No quibbling, no re-charge.
Quiet, quick work confined to the flat area — minimal mess and usually done in a day. You do not need to stay home for external work - we just need power and access agreed in advance.
EPDM can go on in most conditions; GRP needs dry, so we watch the forecast. The Stour valley holds humidity, so drying times lengthen in autumn and moss returns fast on north-facing and tree-shaded roofs.
We install GRP fibreglass, EPDM rubber and torch-on felt flat roofing systems. GRP is our most popular choice for Canterbury extensions — it is fully seamless, handles Kent's wet valley conditions well and typically lasts 25–40 years. EPDM is suitable for larger or irregular areas. We will recommend the right system for your roof area, budget and drainage constraints.
A GRP fibreglass flat roof installed correctly will last 25–40 years in Canterbury conditions. EPDM rubber typically lasts 20–30 years. Torch-on felt gives 15–25 years. Canterbury's valley location and higher-than-average annual humidity mean drainage design is critical — a poorly drained flat roof will fail in 5–10 years regardless of membrane quality.
A small garage roof or outbuilding (up to 20m²) in GRP typically costs £800–£1,800. A standard rear extension flat roof (20–40m²) costs £1,800–£3,500 in GRP. Larger areas, EPDM or complex drainage solutions can reach £4,000–£6,000. We provide free, no-obligation quotes with all drainage and upstand costs included.
Minor delamination or blistering on a felt flat roof can often be repaired if the rest of the membrane is sound. However, if a felt roof is over 15 years old and showing multiple failure points, replacement is usually more economical. GRP overlay onto a sound existing substrate is an option that avoids full strip-off. We will give you an honest assessment on a free site visit.
Yes, with correct design. The key in Canterbury is adequate falls (a minimum 1:80 slope toward the outlet), properly sized drainage outlets that account for the leaf and debris load from the city's mature tree stock, and an upstand of at least 150mm at all abutments. We design every flat roof with Canterbury's specific conditions in mind, not a generic spec.
Yes — we cover the surrounding towns and villages across East Kent:
No call-out fees. No obligation. An honest quote from a local Canterbury roofer who turns up when they say they will.
0122 763 4920 Email Us InsteadHow much does a flat roof cost in Canterbury? See our flat roof cost guide for GRP and EPDM prices.