Flat roofing in Ashford uses GRP fibreglass (£900-£3,500) or EPDM rubber for larger roofs, lasting 25-40+ years. We assess the deck and drainage before installing and include tapered insulation where fall is inadequate. All work carries a written guarantee. Call 01233 877 146 for a free flat roof survey.
GRP fibreglass and EPDM flat roofing for extensions, garages and outbuildings across Ashford. Park Farm and Singleton estate properties are a particular focus — modern extension flat roofs typically fail at 10-15 years and we replace a significant number across these developments each year. Free survey and quote: 01233 877 146.
Ashford's flat roofs are mostly extension, garage and dormer roofs - many built with felt now at the end of its life. GRP fibreglass or EPDM rubber is the modern replacement.
When it is not the answer: If the covering is sound and it is only the flashing or a lap that has failed, a targeted repair beats a full replacement - we will tell you which it is. Read the full guide.
Ashford's rapid housing expansion over the past 30 years — particularly the large developments at Park Farm, Singleton and the International Quarter residential zones — produced a significant volume of flat-roofed rear extensions. The majority were constructed with multi-layer felt systems, which have a typical service life of 10-15 years. Those built in the early 2000s are now well past that point.
We replace these failed felt systems with GRP fibreglass or EPDM rubber depending on size and profile. GRP is our preferred choice for most Ashford extension roofs — seamless, low-maintenance and it handles Kent's thermal cycling well. EPDM suits larger or more complex shapes where GRP lamination is harder to achieve.
Garage flat roof (GRP): £800-£1,800. Small extension (up to 15m² GRP): £1,200-£2,200. Medium extension (15-30m²): £2,000-£3,500. EPDM for large or complex areas: £2,500-£6,000. Prices include removal of existing covering, boarding if required, new system and 10-year guarantee.
📞 01233 877 146
Mon–Fri 8am–6pm · Sat 8am–2pm
We check the deck, falls and existing covering, and confirm whether GRP or EPDM suits the roof and your budget.
Fixed price with the system, insulation (warm deck where required) and trims itemised.
We strip the old felt, inspect and repair the deck, and correct falls where water has been ponding.
We lay the GRP or EPDM system with bonded trims and upstands for a seamless, joint-free finish.
Final inspection, cleanup and a written guarantee on the new roof.
| Job | Typical duration |
|---|---|
| Garage or small extension roof | 1-2 days |
| Larger extension / dormer | 2-4 days |
| Deck replacement (if needed) | Adds a day |
| GRP cure time | Weather-dependent - needs a dry window |
GRP needs dry, above-5C conditions to cure, so we watch the forecast; EPDM is more weather-tolerant. The Stour valley damp can push a GRP job to the next dry window.
Most Ashford flat roofs are low single-storey extensions reached from a tower or ladder; scaffold is needed only for higher dormer or two-storey flat roofs. Scaffold is specified for: dormer roofs, two-storey flat roofs, or where edge protection is required at height - always itemised in your written quote, never a hidden extra, and we arrange it.
Ashford's Victorian terraces around Newtown and Church Road often have rear access only, so scaffold and skip placement need planning; the post-war estates at Bockhanger and Stanhope have driveways that usually take a skip without a permit. Pavement scaffold and skip permits go through Ashford Borough Council; allow a few working days on streets like the terraces around Newtown, Bank Street, the older lanes off Beaver Road where space is tight.
"Extension flat roof on our Park Farm house had been leaking for two years. Previous patches never lasted. They stripped it fully, installed GRP and it's been bone dry through two winters. Should have done it sooner."
"Double garage flat roof replaced with GRP. Done in a day, neat finish and a proper written guarantee. They also pointed out the parapet wall needed repointing — got that sorted too for a fair addition."
"EPDM on a large wraparound extension roof. Complex shape with several upstands and drainage outlets. They handled it without any issues and the finish is excellent. Very professional."
The correct flat roofing system for an Ashford property depends on the size and geometry of the area, the drainage arrangement, and the budget timeline. All three main systems — GRP fibreglass, EPDM rubber and traditional felt — are in active use on Ashford's housing stock, but they have very different performance characteristics and service lives.
GRP (glass-reinforced polyester) fibreglass is our standard recommendation for domestic extension and garage flat roofs up to approximately 40m2. The GRP system is installed as a seamless laminate over a marine-grade plywood deck — there are no seams, laps or joints for water to find its way through. The finished surface is rigid, resistant to foot traffic, and can be walked on for maintenance access without damage. Service life in UK conditions is 25–40 years with minimal maintenance. GRP can be installed in a single day on most domestic flat roofs, minimising disruption.
EPDM (ethylene propylene diene monomer) rubber membrane is the correct specification for larger flat roofs, complex geometries, and areas where GRP installation would be problematic. EPDM is a single-piece membrane adhered to the deck, stretched to accommodate the roof geometry. It is highly flexible, resistant to thermal movement, and has a proven service life of 40+ years in commercial applications. EPDM is also more appropriate than GRP in very cold conditions — GRP requires temperatures above 5C for correct curing; EPDM can be installed in a wider temperature range. On a straightforward domestic extension, GRP is usually preferred for its rigidity and ease of detailing. On a large or geometrically complex flat roof, EPDM is the better specification.
We do not install traditional bitumen felt as a new flat roof system. Felt has a service life of 10–15 years in UK conditions and requires replacement rather than repair when it fails. It has been superseded by GRP and EPDM for all practical purposes. If your existing flat roof is felt and is at end of life, we will quote for replacement in GRP or EPDM rather than like-for-like felt. The additional cost is modest and the service life benefit is significant.
Every flat roof project starts with a deck assessment. The existing deck — the structural boarding beneath the waterproofing layer — is inspected for rot, delamination and structural integrity. Replacement of deck panels where required is included in our quote. We do not install new waterproofing over a compromised deck.
Drainage is the other critical element that is specified before any waterproofing is installed. A flat roof is never truly flat — it must have a minimum fall of 1:80 (approximately 12mm per metre) to drain correctly. Where the existing deck does not have adequate fall built into it, we install tapered insulation to create the correct drainage profile. Ponding water on a flat roof is the primary cause of premature failure in all three main systems.
When stripping a failed felt flat roof on an Ashford extension, the deck condition is frequently worse than it appears from above. Saturated 18mm OSB or plywood delaminates and becomes structurally compromised. We find partially or fully rotten deck panels on a significant proportion of flat roof replacements — typically the areas closest to the drainage outlet where standing water has been longest. We photograph and document deck condition before installing new material and price the deck replacement separately if required after stripping.
GRP and EPDM flat roofs require minimal maintenance. Annual inspection to clear debris from drainage outlets and check the condition of any upstand flashings at parapets and abutments is recommended. GRP can develop hairline cracking over time at upstand joints — these can be relaminated without difficulty. EPDM seams at penetrations and edges are the areas most likely to require attention over the service life. We offer annual flat roof inspection as part of our general roofing maintenance service.
| Job | Typical range | Notes |
|---|---|---|
| Garage roof (EPDM/GRP) | £800 - £1,800 | Typical single garage |
| Small extension flat roof | £1,200 - £3,000 | GRP or EPDM |
| Larger extension / dormer | £2,500 - £5,500 | Size & access |
| Warm-deck upgrade (insulation) | +£400 - £1,200 | Where building regs apply |
| Deck replacement (per m2) | £30 - £55 | If the boards have rotted |
Worked example: a 5m x 4m EPDM rubber roof on a Park Farm rear extension, including deck check, insulation and trims, runs around £2,400.
No large deposit - a small materials payment on larger jobs, balance on completion. Nothing due before materials arrive. VAT included.
Covering TN23, TN24, TN25 and surrounding postcodes.
The installation carries a written 10-year workmanship guarantee; GRP and EPDM systems carry manufacturer material guarantees of 20 years or more on top.
If a fault appears in covered work, we come back and put it right. No quibbling, no re-charge.
Flat roof work is contained to the extension or garage - low noise, little mess, and rooms below stay usable. GRP has a resin smell for a day while it cures. Most of this work is outside, so being home is optional — just sort access and any power we will need beforehand.
GRP needs a dry spell to cure; EPDM can go on in more marginal weather. The Stour valley sits low and damp, a frost pocket that slows drying through autumn and winter, so we build a weather margin into every Ashford booking.
GRP resin gives off a mild solvent smell for a day as it cures, so we ventilate; EPDM rubber has no odour at all and rooms under the extension stay fully usable.A standard garage flat roof in Ashford costs £800-£1,800 for GRP or EPDM. Rear extension flat roofs on Park Farm and Singleton properties typically cost £1,200-£3,500 depending on size and access. Free itemised quotes.
GRP fibreglass is our most recommended system for Ashford extensions and garages. It performs well in Kent's climate, carries a 25-year material lifespan and requires minimal maintenance. EPDM is excellent for larger flat areas.
A properly installed GRP roof lasts 25+ years. EPDM typically lasts 20-25 years. Traditional felt flat roofs, which most Ashford extensions were built with in the 1980s-90s, last 10-15 years. If your felt flat roof is over 12 years old, get it inspected before it fails.
Yes. We handle domestic and light commercial flat roofing across Ashford. Call 01233 877 146 to discuss your requirements.
GRP: 25–40 years. EPDM: 40+ years. Traditional felt: 10–15 years. The system we recommend depends on the roof size and geometry.
EPDM can be installed in most winter conditions. GRP requires temperatures above 5C for correct resin curing — this rules out installation during cold snaps but allows most Ashford winter days to proceed. We assess weather conditions before scheduling and will rebook if conditions are unsuitable.
Like-for-like replacement on the same elevation is permitted development for most properties. Changing the roof form or raising parapet height may require consent. We advise at the survey.
Repeated leaks after repair usually indicate that the underlying deck has been compromised by moisture, that the drainage fall is inadequate and water is ponding, or that the failed waterproofing system has been patched beyond its point of integrity. A full replacement is usually more cost-effective than repeated patching on a flat roof over 15 years old.
Yes. We integrate roof lights — fixed or opening — into flat roof installations as part of the same project. The frame and kerb upstand are included in the flat roof installation. The Velux or rooflight unit cost is additional and confirmed at survey.
Working out the budget? Our Ashford flat roof cost guide breaks down GRP and EPDM prices by size. We also fit rooflights and skylights into flat roofs as part of the same job.
Free survey and system recommendation. We'll tell you whether repair or full replacement makes more sense before you commit.
01233 877 146GRP and EPDM flat roofing across Ashford and all of Kent. See our location-specific flat roofing pages.