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Flat Roofing

Felt, GRP fibreglass and EPDM rubber flat roofs for extensions, garages, dormers and bay roofs — seamless, hard-wearing and built with modern warm-roof insulation.

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The options

Three ways to cover a flat roof

Each has its place. We'll match the covering to how your roof is used, its size, and your budget.

GRP Fibreglass

A hard, seamless glass-fibre finish laid in place. Since it copes well with foot traffic and roof lanterns, it typically lasts 25–30+ years.

EPDM Rubber

A single-piece rubber membrane with very few joints. Because it's quick to fit, flexible and highly reliable, it suits most extensions and garages.

Felt (Torch-on)

Modern high-performance built-up felt. While it costs less than GRP or EPDM, it stays durable for larger or simpler roofs when installed in multiple bonded layers.

What we do

Flat-roof work, done to last

Most flat-roof leaks trace back to old, brittle felt, failed seams, or ponding water sitting where the fall is wrong. We don't just paper over the problem. Instead, we sort the deck and the falls so the new covering performs as it should.

From a leaking garage roof to a new kitchen extension with a roof lantern, we handle the whole job. That means the deck, insulation, covering and all the edge and upstand detailing that keeps water out.

Weighing up materials? See our comparison of felt, GRP and EPDM flat roofing. Or if you've already got a leak, our guide to why flat roofs leak covers the most common causes.

  • New GRP, EPDM or felt flat roofs installed
  • Existing flat roofs re-covered and upgraded
  • Warm-roof insulation fitted to modern standards
  • Correct falls formed to stop ponding water
  • Roof lanterns and skylights weathered in
  • Leaks, splits and failed seams repaired
How it works

A straightforward process

1

Assess the roof

We check the deck, falls and existing covering, then recommend the best system. Since the choice depends on how the roof is used, we look before we recommend.

2

Fixed quote

You get a clear written price for the material and detailing you've chosen. While the job is underway, that price won't change.

3

Install

Deck sorted, insulation and covering laid, upstands and edges weathered in. We work efficiently to limit disruption.

4

Guaranteed

We test for watertightness, tidy up, and back the work with a guarantee. You're left with a clean site and clear paperwork.

Flat roofing questions

What is the best flat roofing material — felt, GRP or EPDM rubber? +
For most London extensions and garages, GRP fibreglass and EPDM rubber outlast traditional felt. GRP gives a hard, seamless glass-fibre finish that copes well with foot traffic and roof lanterns; EPDM is a flexible single-piece rubber membrane that's quick to fit and very reliable. Modern felt is still a cost-effective option for larger or simpler roofs. We'll recommend the right one for your roof and budget.
Can you repair a flat roof or does it need replacing? +
If the deck is sound and the damage is localised — a split, a blister, or a failed seam — we can often repair it. Where the covering has reached the end of its life or water has got into the deck, re-covering is the better long-term fix. We'll tell you honestly which applies to your roof.
What is the difference between a warm roof and a cold roof? +
A warm roof places the insulation above the deck, keeping the structure warm and greatly reducing the risk of condensation — it's the modern standard for flat-roof extensions. A cold roof insulates between the joists below the deck and needs careful ventilation. We build warm roofs on new work wherever practical.
Can you install a roof lantern or skylight on a flat roof extension? +
Yes. Roof lanterns and skylights are a popular way to bring light into kitchen and rear extensions. We form the upstands, weather them in properly with the flat-roof covering, and fit the glazing so it stays watertight for the life of the roof.

Written by the Oldfield Roofing team — roofing and building specialists based in Fulham, covering Fulham, Putney, Hammersmith, Chelsea and Wandsworth.

Flat roof leaking or ageing?

Get a free quote for a repair or a new GRP, EPDM or felt roof built to last. Since every flat roof is different, we'll recommend what actually suits yours.

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