Commercial roofing covers everything from flat-roof warehouses and retail units to office blocks and light industrial premises, and it comes with a different set of rules to a domestic roof: bigger areas, different materials, planned maintenance contracts, and — critically — a lease that usually decides who’s actually responsible for paying when something goes wrong. Getting that responsibility question right, and staying on top of routine inspection, is what keeps a commercial roof from turning a small repair into a five-figure emergency.
Commercial roofing covers any non-residential building — shops, offices, warehouses, industrial units and mixed-use blocks — and is usually a flat or low-pitch roof covering a much larger area than a house. The materials and approach differ from domestic work too: large-format felt or single-ply membrane systems, liquid waterproofing, and roofs designed to carry rooftop plant like air handling units, all specified to standards that reflect the size of the asset and the cost of getting it wrong.
In most UK commercial leases, the tenant is responsible for roof repairs, because most commercial leases are “FRI” — fully repairing and insuring. According to Frettens Solicitors’ guide to commercial lease repair obligations, on a lease of a whole building the tenant typically covers the exterior roof, structure and interior; on a lease of part of a building, the landlord usually stays responsible for the exterior structure and common parts while the tenant covers the interior.
Either way, the actual repair standard — “good and substantial repair,” or matched against a schedule of condition — is set out in the lease itself, and a landlord can inspect the roof and serve notice requiring repairs; if the tenant doesn’t act, the landlord can carry the work out and recover the cost. It’s worth reading the exact repairing clause before assuming either way, since “FRI” doesn’t automatically mean the tenant is on the hook for every scenario.
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Commercial roof repairs typically start from around £150–£400 for a straightforward inspection-led fix, rising well beyond £1,200 for major leaks or larger membrane repairs, since commercial jobs usually involve more roof area and often access equipment a domestic repair wouldn’t need. Per MyJobQuote’s UK roof maintenance cost guide, minor leaks on any roof typically run £150–£400 and major leaks £400–£1,200+, with London and the South East usually running 25–35% above the national average quoted for comparable work.
A one-off roof inspection typically costs £150–£400, while ongoing maintenance work — cleaning, moss removal and protective treatment — adds up depending on scope and roof size:
| Service | Typical Cost |
|---|---|
| Roof inspection | £150 – £400 |
| Roof cleaning | £350 – £800 |
| Moss removal | £300 – £700 |
| Protective treatment / coating | £1,000 – £2,500 |
| Gutter cleaning | £50 – £300 |
Those figures are per visit rather than annual contract rates, and a planned maintenance contract covering two inspections a year is usually cheaper over time than calling a roofer out for every issue individually, simply because most faults get caught and fixed while they’re still small.
Most commercial flat roofs in SouthWest London use either torch-on felt, single-ply membrane, or liquid-applied waterproofing, chosen largely by roof size, the amount of plant and pipework on the roof, and budget. Torch-on felt remains common on smaller commercial units and is straightforward to repair; liquid systems suit roofs with lots of upstands, rooflights or rooftop equipment, since the coating can be applied seamlessly around detail work that sheet materials struggle with.
A commercial roof should be inspected at least twice a year — typically spring and autumn — plus after any severe storm, since a larger roof area gives more opportunity for a small problem (a lifted membrane seam, a blocked outlet, ponding water around plant) to go unnoticed until it’s a leak. Regular inspection is also usually a condition of maintaining a roof warranty on newer commercial systems, so skipping it can cost more than the inspection itself if a claim is ever needed.
An unmaintained commercial roof tends to fail at its weakest points first — blocked outlets causing standing water, perished flashing around rooftop plant, and membrane seams that lift with age — and because commercial roofs cover more area, a small leak can spread and cause internal damage (stock, stored goods, ceiling tiles, electrics) well before it’s obvious from inside the building. Left long enough, what would have been a £300 inspection-and-patch job can become a full re-cover running into the thousands, and if a tenant is on an FRI lease, that bill sits with them, not the landlord.
If you’re weighing up a patch repair against something bigger, our guide to the 25% rule in roofing repair vs replace and our broader roof repair vs replacement guide both cover the same decision, and a proper roof inspection is the fastest way to find out which side of that line a commercial roof is on before it becomes an emergency.
A proper commercial roofing quote should specify the roof system, the area being worked on in square metres, whether it’s a repair, a planned maintenance visit or a full re-cover, and whether access equipment is included — a single vague day-rate figure usually means the scope isn’t fixed yet. Before appointing anyone, our guide on how to hire a roofer covers what to check, and it’s worth confirming any roofer is properly licensed and insured before work starts on a commercial building, where the exposure if something goes wrong is higher than on a house.
JW Roofing Solutions carries out commercial roof repair, maintenance and re-covering across SouthWest London, alongside our full range of roofing services. Every quote is written, detailed and free with no obligation.
Get a free, no-obligation commercial roofing quote from JW Roofing Solutions — we’ll take a look, tell you honestly what the roof needs, and give you a clear written price either way.
Who is responsible for commercial roof repairs, the landlord or the tenant?
Most commercial leases are FRI (fully repairing and insuring), which usually makes the tenant responsible for the roof on a lease of a whole building. On a lease of part, the landlord typically covers the exterior structure while the tenant covers the interior — always check the actual repairing clause in the lease.
How much does commercial roof repair cost in the UK?
Minor leaks typically cost £150–£400 to fix, and major leaks or larger membrane repairs £400–£1,200 or more, with London costs usually running 25–35% above the national average.
How often should a commercial roof be inspected?
At least twice a year, typically spring and autumn, plus after any severe storm — and regular inspection is usually required to keep a roof warranty valid on newer systems.
What roofing systems are used on commercial buildings?
Torch-on felt, single-ply membrane and liquid-applied waterproofing are the three most common systems, chosen based on roof size, rooftop plant and pipework, and budget.
Is commercial roof maintenance worth the cost?
Yes — a planned maintenance contract with two inspections a year is usually cheaper over time than reactive call-outs, since most faults are caught and fixed while they’re still small rather than becoming a major leak or full re-cover.
If you manage or own a commercial property in SouthWest London, contact JW Roofing Solutions for a free, honest assessment and a written commercial roofing quote.
