The short answer
MyBuilder says a flat roof typically lasts 15 to 30 years. By covering, published figures run from around 10 to 20 years for torch-on felt, 20 to 30 years or more for EPDM, 25 to 40 years for GRP and 50 to 100 years for lead. Read them as guides, not guarantees, because poor laying or neglect can bring failure much sooner.
Lifespans by covering
No single number covers every flat roof, because the coverings are so different. The table gathers the ranges published by third-party guides. Where sources disagree the range is wide, and we have kept it that way rather than pick a favourite.
| Covering | Typical published life |
|---|---|
| Torch-on felt | 10 to 20 years (Less, March 2026) |
| EPDM rubber | 20 to 30 years or more (GreenSpec; Less) |
| GRP fibreglass | 25 to 40 years (Less, March 2026) |
| Lead sheet | 50 to 100 years (Less, March 2026) |
The general figure of 15 to 30 years comes from MyBuilder's flat roof guide, updated in August 2026. A roof at the top of any range needs good materials, good laying and sensible upkeep working together. Our wider look at the choices is in the guide to flat roof materials.
Why felt shows the widest spread
Felt covers everything from a quick single layer to a carefully built multi-layer system, and the published figures reflect that. Less puts a good felt job at around 20 years and a poor one at under 10. A trade body, CORC, says well-maintained torch-on felt can reach 30 years or more.
That difference of opinion is mostly down to workmanship. Felt is laid with a flame, the laps must be sealed completely, and the upstands need careful finishing. Skimped work at any of those points shortens the life, whatever the grade of felt. Our guide to how many layers a felt roof needs explains how the build-up works.
Roofs with two or three layers, a fine mineral cap sheet on top and a sealed edge detail tend to sit at the longer end of the published range. A single thin layer on a garage or porch usually sits at the lower end, however neatly it was laid. Choosing the build-up to suit the use of the roof matters as much as the choice of felt itself, and a roof that people walk on, or one that sits under a tree, wants a tougher specification than a small canopy.
EPDM and GRP: long lives with a catch
EPDM is a synthetic rubber membrane supplied in large sheets, stuck or fixed down onto the deck. Less describes manufacturer warranties of 20 to 25 years as standard, but a warranty term says nothing about how long the roof itself survives, and it protects the product, not the whole build. GRP, short for glass-reinforced plastic, is a fibreglass resin laid in place to form one jointless skin, and is usually quoted at 25 to 40 years.
The catch with both is the details. A sheet or skin can outlast the edges, outlets and joints around it. If the trim loosens or a corner was stuck down poorly, water gets in long before the main surface is worn out. Choosing between the two is covered on our page about EPDM against GRP.
Where a roof is pinned by the ranges above, remember that every figure assumes a sound deck. A covering laid over wet or rotten boards will not reach its range, and the cost of that mistake lands years later, when the roof is already paid for. A modest sum spent on the deck at the start is often the best value in the whole job.
Lead: the long-lived outlier
Lead sheet sits well above the others at 50 to 100 years in Less's figures. MyJobQuote adds that lead flashing, correctly installed, can outlast 80 years, and 100 in the heavier codes. A lead code is the sheet's thickness grade, with higher numbers meaning thicker lead.
That longevity comes at a price, and lead is normally chosen where the building, the budget and the appearance justify it, such as a small bay roof or a listed building. It can still fail through poor detailing, and it needs fixings that let it expand and contract with the temperature. Our guide to warm and cold flat roofs shows how the structure beneath affects any covering.
What shortens a flat roof's life
Standing water is the largest single cause of early failure, since it keeps the surface wet, supports algae and works into small defects. Foot traffic comes next. A roof used as a terrace without a proper walking surface wears out faster, and so does one where tradespeople have walked with sharp tools.
Other factors are overhanging trees that drop debris, blocked outlets, damaged trims, poor ventilation that traps moisture, and a deck that moved or rotted. Direct sun ages bitumen and plastics over time. A roof laid over a damaged deck without repair starts life with a short clock. Our page on whether flat roofs leak covers where leaks usually begin, and flat roof leak signs shows how to spot an old roof running out of road.
Making the most of the life you have
Sweep leaves and silt off the surface, and free the outlets, a couple of times a year, especially after autumn. Look for lifted laps, loose trims and standing water after heavy rain, and have small faults fixed early. Keep heavy items off the roof, and keep anything sharp away from it.
Thinking of laying fresh covering over old? The rules and risks are on our page about overlaying a flat roof. To find out where yours stands, ask for a survey: we photograph the roof and send a written quote. Our workmanship guarantee runs for 10 years, in writing, apart from whatever warranty the manufacturer gives the material. Everything we do on flat roofs is listed on our flat roofing page.