A commercial roof is a depreciating asset that almost nobody looks at until it leaks. Planned maintenance is cheap, coating systems can genuinely add a decade to a sound sheet, and both are routinely sold to owners whose roof is past the point where either helps. The distinction is not marketing, it is measurable, and it is what a survey exists to establish.
What maintenance on a commercial roof actually is
Clearing outlets and gutters, which is the single highest value job and the one most often skipped. Checking and replacing fasteners that have backed out or corroded. Resealing laps and details that have opened. Inspecting every penetration added since the last visit, because somebody else's cable tray or condenser is a common source of new leaks. And a written record with photographs, because that record is what an insurer and a future purchaser will ask for.
When coating and cut edge treatment work
On a profiled metal roof, corrosion usually starts at the cut edges of the sheets and around the fixings rather than in the middle of the panel. Cut edge corrosion treatment cleans and encapsulates those edges, and a coating system over a sound sheet then buys years of further life at a fraction of replacement. That works while the sheet is intact. On a roof that has already perforated in the field, coating it is painting over a hole, and the survey that distinguishes the two is worth what it costs.
Restoration against replacement
Restoration keeps the existing structure and covering and renews the weatherproofing. Replacement resets everything including the insulation, which is the part that changes the building's running cost and which the Building Regulations reach when a thermal element is replaced. The right choice is usually decided by lease length and by whether the insulation is wet: dry insulation and a sound sheet favour restoration, a saturated build up favours replacement whatever the sheet looks like.
Questions people ask about commercial roof maintenance
How often should a commercial roof be inspected?
Annually is the common standard, and many leases and insurance policies require it. Twice a year, after autumn leaf fall and after winter, is better on a roof with valley gutters.
Is a roof coating a permanent repair?
No, and reputable systems do not claim to be. They are a service life extension on a sound substrate, with their own guarantee period, and they need the same maintenance regime afterwards.
Can cut edge corrosion be repaired without scaffolding the whole roof?
Usually yes, with rope access or mobile edge protection, because the work is at the sheet ends rather than across the field. The access method should be in the quote.