How long does a commercial roof last?

No commercial roof has a single fixed life. The published guides give typical ranges for each covering, and they disagree a little, because age depends on how a roof was laid and looked after.

• Built-up felt: 10 to 20 years (Less, March 2026). The same guide says careful laying can take felt to 20 years, while poor workmanship may end it inside 10.
• EPDM rubber sheet: 20 to 30 years (GreenSpec). Less gives 30 to 50 years.
• GRP: 25 to 40 years (Less).
• Concrete tiles on a pitched hall or unit: around 60 years, in Marley's words, who add that this is not a guarantee.
• Zinc: in excess of 100 years (the maker VM Zinc, citing a Building Research Establishment declaration). Lead flat roofs: 50 to 100 years (Less).

Profiled steel, PVC and polyolefin membranes are missing from that list because their life follows the product data sheet and what a survey finds on your roof.

Standing water is the big one. A membrane that sits under a pond for weeks ages faster than one that drains, so falls matter. BS 6229:2025 keeps a minimum finished fall of 1:80, and roofers usually design for something steeper so the finished roof still clears. Our answer on ponding on commercial flat roofs covers what to do when it does not.

Next comes traffic. Engineers who service air handling units or fit signage walk the same route again and again, and a membrane worn along that path fails first. Blocked outlets, leaf debris and gutters that overflow back onto the roof come after, followed by weak details at upstands, parapets and edges, and these are the spots where an otherwise healthy roof tends to start letting water in.

Sea weather and strong sun add to all of this on our stretch of coast, which is one reason a roof near the front can need more attention than the same build inland.

Start with the paperwork. A date for the last full recovering, any manufacturer data sheet and a record of earlier repairs tell a surveyor far more than a glance from the ladder. A roof carrying many small patches is telling you something, even if each patch is holding.

Then the roof itself. Look for seams lifting or splitting, blisters in felt, a crazed or chalky surface on a coating, tide marks of dirt where water stops, and sheets that feel brittle underfoot. On metal, orange lines along cut edges and brown streaks below the laps point to a covering that is ageing; the cut-edge corrosion guide in our commercial section explains how that starts.

Photographs of each defect, with a written note on what they show, turn those impressions into a plan. The verdict on the roof as it stands is one of three: mend it, hold it together for a season, or recover it. We price the smallest job that will properly cure the fault.

Most of what extends a roof's life is dull. Clear outlets and gutters, and do it after storms as well as on a routine. Remove debris before it holds water. Re-seal a failing lap or flashing early, while the repair is still a small one, and keep contractors off the membrane except on marked walkways with protection laid down.

A written maintenance visit with photographs also builds a record. When the day comes to choose between mending and recovering, that record shows how the roof has behaved, which makes the verdict easier to trust and easier to explain to a landlord, a board or a lender. Our page on commercial roof maintenance sets out what a visit looks at.

Keep fragile roofs in mind too. Old sheets and rooflights can fail underfoot, so plan access for anyone who goes up there, from the plant engineer to the window cleaner, instead of improvising it on the day.

A manufacturer's warranty runs for a fixed term and carries conditions. It describes what the maker will stand behind on paper. It says little about how long the roof will keep water out in practice, and a roof can outlast its paper cover or give up before it ends. Ask what the conditions are, who must carry out the work to keep them valid, and what upkeep the warranty expects from you.

Plan the replacement while the roof still works. Once repairs become frequent, or a survey finds wet insulation or corroded sheets across a large area, patching costs more over time than recovering. Our guide to repair or replace on a commercial roof walks through that call.

Size, access, the new covering and the survey findings set the cost. Our commercial roofing work begins with that survey, after which we put a single total price in writing.