Flat Roof Repair in London
Leaking flat roof over your extension, dormer or garage? We repair felt, EPDM rubber and GRP fibreglass flat roofs properly — from honest patch repairs to full overlays that last decades.
Flat Roof Repairs We Carry Out Every Week
London is full of flat roofs — kitchen extensions, dormers, garages, porches — and most fail at the details: a split seam, a blistered patch, a failed outlet. We inspect the whole roof surface before quoting, because a cheap patch over a rotted deck is money wasted. You get photographs, plain-English findings and a fixed price for the right repair.
Felt Roof Repairs
Blisters cut out and resealed, cracked pour-and-roll felt patched with heat-applied torch-on felt, and tired perimeters re-detailed. Where the whole covering is shot, a three-layer torch-on overlay goes straight over the old roof.
EPDM Rubber Repairs
Splits and seam failures on EPDM roofs repaired with proper EPDM primer and self-adhesive flashing — the manufacturer-approved method, not generic sealant. Worn roofs get a new EPDM overlay sheet.
GRP Fibreglass Repairs
Cracked or crazed GRP re-matted and re-topped with a fresh layer of fibreglass and flowcoat. Flaking topcoat — the most common GRP complaint — is stripped and re-sealed to stop leaks at source.
Decking Replacement
Soft, spongy boards mean water has got through and rotted the deck. We cut out the failed OSB or ply sections, lay new 18mm decking, and then re-cover the area to match.
Outlets & Drainage Fixes
Ponding water is the slow killer of flat roofs. We clear, repair or reposition outlets and scuppers, and where falls are wrong we advise on tapered insulation to get water moving again.
Flashing & Upstand Renewal
Failed felt or lead flashings where the flat roof meets the wall are the leak point we find most often on London extensions. We cut chases and re-flash the upstand properly.
Honest Price Bands for London Flat Roof Repairs
As a rough 2026 London guide: a straightforward patch repair on a felt or EPDM roof typically costs £250 to £600; decking replacement plus re-covering a localised area runs £600 to £1,500. Where the whole covering is failing, a full overlay usually costs £90 to £140 per square metre for EPDM and £80 to £120 per square metre for torch-on felt — a typical 20m² extension roof often lands between £2,500 and £5,000 all-in. Our free inspection gives you a fixed written quote for your roof's actual condition, not a ballpark that changes later.
6 Signs Your Flat Roof Needs a Repair
- Water staining on the ceiling below. On extensions and dormers the stain usually sits right under the failed area — act fast before plasterboard and joists are damaged.
- Blisters, bubbles or ripples in the surface. Trapped moisture under felt or GRP expands in heat and splits the covering. They never get better on their own.
- Ponding water that lingers for days. A shallow puddle after rain is normal; water still sitting 48 hours later is stressing the covering and rotting the deck.
- Cracks, splits or crazing. Fine spiderweb cracking on GRP, or splits along felt laps, are direct routes for rain — they need sealing or re-covering.
- Moss, algae or vegetation. Green growth means the surface stays damp. Roots and rhizomes work into tiny cracks and prise them open.
- Soft, spongy patches underfoot. If the roof feels bouncy when you step on it, the deck underneath has rotted and needs cutting out — a patch on top will not hold.
Why London Trusts Victoria Roofing
Family-run since 1982
Over 40 years roofing London's extensions, dormers and garages. The same family name stands behind every job.
5.0 from 338 Google reviews
Hundreds of five-star reviews from London homeowners, many for flat roof repairs that have stayed dry for years.
Free, no-obligation quotes
We walk the roof, photograph every problem, and give you a fixed written price for the right repair — patch or overlay, no upsell.
Fully guaranteed workmanship
Every flat roof repair is backed by our workmanship guarantee. If it leaks again, we come back and put it right.
Open 24 hours
A flat roof leak does not wait for Monday. Call 07848 256099 any time for emergency make-safe work.
Covering all London
From 188 Camden High St, London NW1 8QP, our teams repair flat roofs across every London borough, every day.
Flat Roof Advice From Our Blog
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Flat Roof Repair Across North & Central London
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Flat Roof Repair Questions, Answered
A straightforward patch typically costs £250 to £600, while a localised decking replacement with re-covering runs £600 to £1,500. If the whole covering is failing, a full overlay usually costs £80 to £140 per square metre depending on the system — a typical 20m² extension roof often lands between £2,500 and £5,000. Our free inspection and fixed written quote remove the guesswork.
Yes — if the covering is generally sound and the deck beneath is dry, localised repairs are perfectly good practice. We patch felt with heat-applied torch-on material, EPDM with manufacturer-approved self-adhesive flashing, and GRP with re-matting and flowcoat. If we find widespread failure or rotted decking, we will tell you honestly that an overlay or replacement is the better spend.
A well-executed patch on a sound roof should last 5 to 10 years or more. A full overlay effectively gives you a new roof: a three-layer torch-on felt system typically carries a 15 to 20-year life, EPDM commonly lasts 25 to 30 years, and GRP around 25 years. All of our workmanship is fully guaranteed regardless.
Usually not. Most extension, dormer and garage flat roofs are reached by ladder or from an upper window, so there is no scaffolding cost. Where the roof is high, awkward or shares a boundary with a neighbour, we may recommend a small tower — we will say so clearly in your quote rather than surprising you later.