The short answer
A commercial roof should be inspected every year, with an extra visit after severe storms and a clear-out of outlets and gutters in autumn. Older roofs, roofs carrying plant or solar panels and roofs with a leak history justify more frequent visits. Each inspection should produce a dated written report with photographs, which doubles as the maintenance record insurers ask for.
A regime, not a single visit
There is no law that fixes one interval for every commercial roof, so the right frequency is a judgement about the building. A reasonable starting point is a planned visit once a year, ideally in autumn before the wet months, with a second look in spring when winter damage is easiest to spot. On top of that sit event-driven visits: after a named storm, after heavy snow, after any work by other trades on the roof and after any leak.
Frequency rises with risk. Roofs that are old, complex, poorly drained or covered in plant deserve more attention than a simple new sheet roof. Buildings where a leak would be costly, such as food stores, data rooms or archive space, justify closer watching. A roof with a history of repeat repairs is a candidate for visits more often than once a year until the cause is cured.
The aim is to catch small faults while they are still small and cheap to put right. Our answer on how long a commercial roof lasts explains how maintenance moves a roof within its typical range.
What a proper inspection covers
A drive-by look from the car park is not an inspection. A proper one walks the roof, or uses safe access methods where walking would damage it, and records condition against a checklist.
- The covering. Splits, blisters, ponding, lifted laps, open seams, cracked or crazed areas and signs of repeated patching.
- Outlets, gutters and valleys. Blockages, debris, standing water and the condition of linings.
- Edges and junctions. Upstands, copings, flashings and the interface between the roof and walls.
- Penetrations. Vents, flues, pipes and plant supports, and the seals around them.
- Rooflights. Cracks, brittle surfaces, loose fixings and their safety guards.
- Fixings and metalwork. Rust, loose screws and cut-edge corrosion on metal roofs.
- Inside. Staining, drips and damp patches on ceilings and walls below.
The roof also has to be safe to inspect, with a fall arrest or edge protection plan in place. The page on roof fall arrest systems deals with that.
Reading the report
The product of an inspection is a report, and the report is more useful if it follows a plain structure. It should name the roof and the date, describe the covering and the access, list defects by location with a photograph for each, rank them by urgency and recommend a remedy. It should distinguish between what must be done now, what should be done this year and what can be watched.
Photographs are the heart of it. A picture of a split seam with a tape measure beside it tells the reader more than a paragraph of description, and a set of pictures from year to year shows how a defect has changed. They are also what you can send to a landlord, a surveyor or an insurer if questions arise.
Where the report finds a suspected wet-insulation problem, further tests may be proposed, such as moisture mapping or core samples. Those are optional extras to a routine visit, and the report should say why they are suggested. Where it finds asbestos-containing material or suspects it, the next step is to have it identified properly before anyone disturbs it. See asbestos on an industrial roof.
Routine clearance and small jobs between inspections
Inspection finds problems; maintenance prevents them. The most valuable routine job is clearing outlets, gutters and valleys of leaves, silt, moss and windblown rubbish, and autumn is the time to do it. Blocked drainage is behind a large share of avoidable leaks, and it costs little to put right.
The other routine tasks are small: re-sealing a lap, replacing a perished washer, refixing a loose flashing, clipping back vegetation, clearing moss before it lifts a seam and making good a worn walkway. Done during the inspection visit, they save a second trip and, often, a second access set-up.
Plant engineers who service units on the roof should use designated walkways, and the roof file should record each visit so that damage can be traced. A programme that combines inspection and minor works is covered on our commercial roof maintenance page, and a contract that fixes the visits in advance is described under roof maintenance contracts.
Why the inspection record matters
A dated series of reports does several jobs at once. It tells you the roof's condition, lets you budget for repairs before they become emergencies and shows a surveyor or buyer that someone has been watching the roof. It is also the evidence insurers look for when a loss occurs, as our answer on what commercial property insurance expects of a roof explains.
For a tenant, an inspection record helps in discussions with the landlord about who is liable for what. For an owner, it informs the choice that comes as a roof wears out, and when repairs begin to stack up the page on repairing or replacing a commercial roof helps you weigh up the options. If roof work must happen on a working site, roof work while the business stays open explains the usual arrangements.
To start a record, book a survey. The first inspection from us is free, comes with photographs of the roof as it stands, and any work arrives as a written fixed price. Our other services for businesses sit under commercial roofing.
