Flat roofing specialists covering Corsham and the SN13 area. GRP fibreglass and EPDM rubber for extensions, garages and period property additions. Conservation area compliant. 25-year warranty. Free quotes.
Flat roofs fail at the surface and the details: a blistered or split membrane, standing water that never clears, or a leak at an upstand or outlet. Most Bath flat-roof problems are old felt reaching the end of its life.
Water ponding on the roof days after rain
Blisters, splits or cracks in the felt or covering
A leak into the room or extension below
Felt lifting at edges or around the outlet
A roof that's been patched repeatedly
When it is not the answer: If your flat roof is a sound GRP or EPDM system under 15 years old with one isolated fault, a targeted repair is far cheaper than a full replacement — we'll tell you honestly which you need. Read the full guide.
Warm deck versus cold deck flat roof construction compared
Flat Roofing in Corsham
Flat Roofing Corsham
Flat roofing in Corsham spans two distinct markets: conservation area period properties requiring sympathetic materials and planning compliance, and standard post-war estate housing where GRP fibreglass offers the most practical and cost-effective flat roof replacement. Both are well represented across SN13 and we are experienced with each.
GRP Flat Roofing in Corsham
GRP fibreglass is our recommended flat roofing system for most Corsham properties. It is seamless, handles SN13's elevated exposure and above-average rainfall well, and carries a 25-year manufacturer warranty. A standard garage flat roof in Corsham is typically completed in a single day. The Corsham Court parkland tree canopy increases debris accumulation in gutters and on flat roof surfaces around the town centre — GRP's smooth surface is more resistant to moss growth and easier to maintain than felt alternatives.
Conservation Area Flat Roofing
GRP is accepted for flat roof surfaces not visible from the public realm on most Corsham conservation area properties. Where the flat roof is visible or on a listed building outbuilding, lead may be required by the planning authority. We advise on the planning position for every Corsham conservation area flat roof job and confirm the appropriate system before work starts.
Flat Roof Costs in Corsham
Garage flat roof (GRP): £900–£1,800
Extension flat roof (GRP, up to 20sqm): £1,500–£3,000
Lead flat section (conservation area): £120–£220 per sqm
Free quotes for all sizes. No call-out fee.
For a flat roofing quote in Corsham call 0122 528 7924. We advise on conservation area requirements at no charge.
Our Process in Corsham
Flat Roofing in Corsham: How We Work
Free Assessment
Every flat roofing job in Corsham starts with a free assessment visit. We inspect the full roof condition — not just the reported problem — and give a written fixed price before any work starts. No call-out fee for the assessment. No obligation to proceed.
Local Knowledge
Corsham's housing stock has specific characteristics that affect how flat roofing work is specified and carried out. We have been working across SN13 for over 20 years and understand the local materials, construction methods, and planning requirements that apply to your property type.
What Good Completion Looks Like
At the end of every flat roofing job in Corsham we carry out a site check: confirm the work is complete, clear all debris, and ensure drainage is running correctly. You receive a written confirmation of the work done and a guarantee certificate. For any job over 500 pounds we provide a full written specification of materials and methods used.
The process
How a Corsham Flat Roofing Job Runs
1. Survey
We inspect the deck, falls and current covering, and identify why it's failing rather than just patching the symptom.
2. Recommend & quote
We recommend GRP or EPDM based on the roof and setting, and quote a fixed price including any deck and insulation work.
3. Scheduling
We book the job — most flat roofs are a one to three-day project — and confirm access.
4. Strip & re-lay
We strip to the deck, re-establish proper falls, upgrade insulation to current regs, and lay the new seamless covering.
5. Finish & sign-off
We complete the trims and outlets, clear the site, and hand over your guarantee and any manufacturer warranty.
Timescales
Job Durations at a Glance
Job
Typical duration
Flat roof repair
2–4 hours
Garage flat roof (GRP/EPDM)
1 day
Extension flat roof
1–2 days
Large or multi-level flat roof
2–4 days
Deck replacement
+1 day
GRP needs dry conditions to cure, so we watch the forecast and won't lay fibreglass into rain — EPDM is more weather-tolerant.
Access
Getting Safely onto Corsham Roofs
Most Bath flat roofs are reached from a tower or ladder; scaffold is added only for higher or awkward extensions and is itemised. Scaffold is specified for: first-floor and above flat roofs, or where edge protection is required - always itemised in your written quote, never a hidden extra, and we arrange it.
Corsham's Bath stone terraces and listed cottages need lime-mortar-aware access; the historic High Street has tight pavements. Pavement scaffold and skip permits go through Wiltshire Council; allow a few working days on streets like High Street, Pickwick Road, Church Street where space is tight.
Pricing
What Flat Roofing Costs in Corsham
Job
Typical range
Notes
Flat roof repair
£150–£450
Isolated fault
Garage flat roof (EPDM)
£800–£1,800
Single-ply rubber
Garage flat roof (GRP)
£1,000–£2,200
Seamless fibreglass
Extension flat roof
£1,800–£4,000
Size dependent
Large/multi-level flat roof
£3,000–£6,000+
Incl. insulation upgrade
What moves the price
Roof area and number of outlets, upstands and details
GRP fibreglass vs EPDM rubber vs the setting
Whether the deck and insulation need replacing to meet regs
Access height on first-floor and above extensions
Worked example: A GRP fibreglass replacement on a typical rear kitchen extension in Bear Flat, including a new deck and upgraded insulation: around £2,600.
No deposit on flat-roof repairs under £500. Staged payment on full replacements, balance on completion — never anything before materials are on site. VAT included.
Covering SN13 and surrounding postcodes.
Guarantee
Your Guarantee, Explained
Our flat-roof workmanship is guaranteed for 10 years; GRP and EPDM systems carry manufacturer warranties of 20–25 years on top when installed to spec.
Covered: workmanship for 10 years, in writing, transferable if you sell.
On top: manufacturer warranties on materials (terms vary by product).
Not covered: storm or impact damage - that is an insurance matter, and we will document it for your claim.
If a fault appears in covered work, we come back and put it right. No quibbling, no re-charge.
Good to know
What It Is Like While We Work
Flat roofing is quiet, quick work with minimal mess — usually done in a day or two with the old covering taken away and the area left clean. You do not need to stay home for external work - we just need power and access agreed in advance.
GRP laying waits for a dry window; EPDM can go on in most conditions. Either way we never leave a deck exposed overnight. Corsham's exposed plateau position on the Cotswold edge catches more wind than the sheltered Bath valley.
Customer Reviews
Recent Jobs
★★★★★
“GRP on our rear extension in Neston. Done in one day, no disruption, 25-year warranty. The old felt had been leaking every winter for two years.”
Ade V. · Neston, Corsham
★★★★★
“Outbuilding flat roof on our listed property near the High Street. They confirmed the GRP was acceptable for this particular roof surface, did the job neatly, and documented everything for our listed building file.”
Audrey H. · Corsham High Street
★★★★★
“Emergency flat roof repair after a storm. They attended within three hours, made it watertight, and we had GRP installed the following week. No call-out fee, honest pricing.”
David L. · Corsham SN13
Maintenance Guide
Keeping Your Flat Roof in Good Condition
Outlet Inspection — The Most Important Task
The single most important maintenance task for any flat roof is keeping the outlet clear. A blocked flat roof outlet during heavy rainfall can fill the roof surface with standing water in minutes. The weight of standing water — approximately 1 tonne per cubic metre — stresses the deck, forces water into any existing membrane weakness, and can cause sudden deck failure in severe cases. Outlets should be checked and cleared in late autumn after leaf fall, again in spring after pollen and moss season, and after any period of heavy storm debris. The inspection takes two minutes and prevents the most common flat roof emergency.
What GRP Maintenance Looks Like
GRP fibreglass flat roofs require minimal maintenance compared with felt alternatives. The gelcoat surface should be inspected annually for any chips, cracks, or impact damage — these are typically small and easily repaired with GRP repair resin before they develop into through-membrane leaks. The edge detail and upstands should be checked for any lifting or gap formation at the wall junction. Standing water that does not drain within 48 hours of rainfall indicates either a blocked outlet or an inadequate drainage fall — both should be investigated rather than ignored.
How Long Your Flat Roof Should Last
A correctly installed GRP flat roof has a design life of 30 to 40 years. The 25-year manufacturer warranty covers membrane integrity — not storm damage, impact damage, or maintenance-related failures such as outlet blockage. In practice, GRP flat roofs installed in Bath over the past 20 years are performing well with no significant membrane failures where the installation was carried out correctly and outlets have been maintained. The most common cause of premature GRP failure is incorrect fall specification at installation — water pooling on a GRP surface does not cause immediate failure but accelerates surface degradation over time.
FAQ
Frequently Asked Questions
A garage flat roof in GRP costs 900 to 1,800 pounds. Extension flat roofs up to 20 square metres cost 1,500 to 3,000 pounds. Free quotes for all sizes and property types.
In most cases yes, for surfaces not visible from the public realm. We confirm the planning position for every conservation area Corsham flat roof job before recommending a system.
A correctly installed GRP roof has a design life of 30 to 40 years and carries a 25-year manufacturer warranty. It handles Corsham's elevated exposure and tree canopy environment well.
Where less than 20 percent of the surface is affected, repair is often viable. We assess this honestly on every visit and never recommend replacement when repair is the right answer.
A standard garage or small extension flat roof in Corsham is completed in one day for GRP. Larger or more complex roofs with multiple abutment details take 2 to 3 days.
Yes. We cover Corsham 24/7 for flat roof emergencies. Call 0122 528 7924 at any time.
Yes. EPDM is an alternative to GRP for larger or more geometrically complex flat roofs in SN13. We recommend the appropriate system for each job. Free quotes for both systems.
Free Corsham Roofing Quote
No call-out fees. No obligation. Free assessment and honest quote before any work starts.
