The short answer
It depends on the system, and published ranges differ. HomeBuilding gives felt 10 to 15 years, GRP 25 to 30, EPDM 25 to 30 and lead 60 to 100, while Less gives felt 10 to 20 years, GRP 25 to 40 and EPDM 30 to 50. Maintenance and detailing move a roof within or outside its range. A lifespan is a typical figure, never a promise.
Ranges by system
The figures below are typical lifespans as published in cost guides, offered for orientation and not as predictions for a particular building. HomeBuilding & Renovating (Sep 2025) lists felt at 10 to 15 years, GRP at 25 to 30 and EPDM at 25 to 30, with lead as a flat roof covering at 60 to 100. Less (Oct 2026) gives felt at 10 to 20 years, GRP at 25 to 40 and EPDM at 30 to 50.
The two guides disagree on EPDM, a synthetic rubber membrane laid in large sheets, so both are named. The difference shows how loosely the term lifespan is used, and why the number on a brochure should be treated with some caution.
Metals sit at the long end. Lead flashing can last for over 80 years according to MyJobQuote, a lower bound, and the zinc maker VM Zinc cites a BRE environmental declaration of 100 years. They come from different sources and neither is a guarantee.
For profiled metal sheets, composite panels and fibre cement, life depends heavily on the coating, the environment and the fixings, so a survey of your roof says more than a table can.
Our guides to single-ply roofing and built-up felt roofing explain how each system is laid.
What shortens or lengthens a roof's life
Within any range, a few factors do most of the work. Drainage is the first. A roof that holds water ages faster than one that sheds it, and blocked outlets leave it holding water. Falls that were set correctly at the start keep a membrane drier for longer.
Detailing is the second. Leaks on flat roofs often begin at the edges, penetrations and junctions, not in the middle of a sheet. A well-made upstand, a properly sealed pipe and a sound flashing add years that the material alone cannot supply.
Use is the third. Foot traffic, plant maintenance, heavy hail, chemical deposits and heat from vents all wear a covering. A roof with a walkway and protected plant bases outlasts one where engineers walk everywhere.
Workmanship counts too. Seams welded or bonded properly, laps made correctly and fixings chosen for the sheet make the difference between a roof that reaches its range and one that fails early. Poor preparation of the deck beneath shows up years later.
Finally, maintenance. A planned visit clears debris, finds small defects and keeps the roof in the upper part of its range, as our answer on commercial roof inspection frequency sets out.
Never a promise
A lifespan is a typical figure drawn from experience, and it forecasts nothing about any one roof. Marley, discussing roof tiles, makes the point plainly: a life expectancy of around 60 years is no warranty of longevity. The same holds for every covering.
It is also worth separating a lifespan from a warranty. A warranty is a contract with terms and exclusions, usually shorter than the covering's life and often conditional on maintenance. Its length is a commercial term, not a forecast of service life in your conditions.
Use ranges for planning, not for certainty. Budget for a replacement toward the later part of a range, and bring the date forward if inspections show signs of age: crazing, splitting seams, shrinkage at edges, widespread corrosion or repeated leaks.
Where a roof is approaching the end of its range but is still sound, repair may be the better buy. Where defects are widespread, repair only delays the inevitable, and we say which it is, with photographs, before a price is given.
Planning replacement, and what we do
Planning ahead is cheaper than reacting. A roof reaching the later part of its range deserves a survey that records its condition, and a sum put aside for renewal. That gives the owner time to choose a covering, arrange access, plan the work around the business and compare proposals calmly, instead of paying for an emergency.
When a renewal is due, the covering is chosen to suit the building: the loads the structure can carry, the falls available, the insulation needed and the use of the roof. Overlaying may be possible, which saves removal, or stripping may be necessary if wet insulation or a damaged deck makes it unavoidable.
We survey, photograph what we find and explain what is failing and what is not. Then we give one written total for the work that the survey supports, so the choice between repairing, overlaying and renewing rests on the same evidence.
For the wider choice of systems, see our commercial roofing page, and for membrane choices our answer on PVC roof membrane lifespan.
