Use this checklist to walk a commercial roof or to check that an inspector covered everything. Work through it in order, photograph what you find, and mark each item as sound, monitor or defect. A checklist with a photograph and a date behind every line is a record. A checklist with ticks alone is not.
Only go on a roof if it is safe to do so, with fall protection and a second person present. If the access is poor, the surface is fragile or the weather is wrong, stop and book someone equipped for it. No line on this page is worth a fall.
How to use it
Print it, or copy it into whatever you already use for maintenance records. Then work in this order:
- Read the history first. Last report, repair invoices, warranty paperwork and any interior leak complaints.
- Walk the interior before the roof. Stains tell you where to look hardest once you are up there.
- Walk the perimeter, then the field. Most failures are at edges and details, so start where the problems are.
- Photograph as you go. Every defect gets an image with a fixed reference in frame, such as a unit, a drain or a corner, so it can be found again.
- Rank before you leave. Urgent, this year, or monitor. Ranking on the roof is more accurate than ranking from memory at a desk.
Before you go up
- Review the last inspection report and repair records
- Note any interior leaks, with dates and locations
- Confirm safe roof access and fall protection
- Check the weather. A wet or icy roof is not a roof to walk
- Note who has been on the roof since the last visit, and why
Membrane field
- Splits, cracks or punctures
- Blisters, ridges or wrinkles
- Worn or missing surfacing, such as granules or gravel
- Soft or spongy areas underfoot
- Shrinkage pulling the membrane tight at corners and curbs
- Damage in traffic routes between access points and equipment
Soft underfoot is the most important item in this section and the easiest to walk past. It usually means the insulation below is wet, and wet insulation spreads sideways well beyond the hole that let the water in. Mark the extent of every soft area with chalk and photograph it, because the size next visit is the measurement that matters.
Seams and laps
- Open, lifted or fishmouthed seams
- Failed tape or adhesive on rubber roofs
- Seams tested by hand or with a probe, not judged by eye alone
- Patches from previous repairs still bonded at their edges
A seam that looks sound from standing height can still be open. Run a blunt probe along suspect laps rather than trusting a glance, and pay particular attention to seams that cross a change in slope or run into a detail.
Flashings and edges
- Wall and parapet flashings sealed and attached
- Edge metal secure, with no gaps or rust
- Counterflashing and sealant intact
- Termination bars fixed, with no loose or missing fasteners
- Coping joints closed and sloped inwards
- Reglets and through wall details free of open gaps
Edges take the highest wind loads on the roof, which is why storm damage usually starts there. If you only have time for part of the roof, do this section.
Penetrations and equipment
- Pipe boots and pitch pans sealed
- Curbs around rooftop units flashed and dry
- Equipment panels closed, condensate draining away from the roof
- No debris left by other trades
- Conduit and pipe supports sitting on pads, not directly on the membrane
- Gas lines, cable trays and satellite mounts properly flashed
- Skylights and smoke vents sealed, with intact glazing or domes
This is the section that rewards opening things. A closed panel hides a condensate line dripping onto the membrane, and a drip in the same spot for a year does more damage than a puncture.
Drainage
- Drains, strainers and scuppers clear
- Gutters and downspouts attached and flowing
- Ponding areas marked and photographed
- Overflow drains or scuppers present and clear
- Sumps clear below the strainer, not just at the surface
- No debris likely to migrate to a drain in the next storm
Ponding is worth measuring rather than noting. Photograph the same puddle from the same spot every visit. A ponding area that grows year on year is telling you about deflection in the structure or crushed insulation, and that is a different conversation from a blocked drain.
Interior
- Ceiling tiles checked below known problem areas
- Deck underside checked for rust or stains where visible
- Insulation in accessible voids checked for damp or staining
- Walls below parapets and at roof junctions checked for tide marks
- Occupants asked what they have seen, and when
Occupants are an underused instrument. Someone who works under the roof every day knows which ceiling tile marks after heavy rain and which one only marks when the wind is from a particular direction. Ask before you go up.
What changes by roof type
The structure of the walk stays the same. What you look hardest at does not.
| Roof type | Look hardest at |
|---|---|
| TPO and PVC | Seam welds, shrinkage at perimeters, punctures in traffic routes |
| EPDM | Taped seams, membrane pulled away from walls and curbs, patch edges |
| Modified bitumen | Blisters, splits, lifted laps, condition of the cap surfacing |
| Built up | Bare spots in the gravel, ply splits, blisters, flashing bitumen gone brittle |
| Metal | Fasteners, washers, seam openings, rust at cut edges, sealant at details |
| Any type | Drains, edges, curbs, penetrations, and anywhere a trade has been working |
A building re roofed in stages may have two or three of these on one structure. Treat each section as its own inspection, because the failure pattern and the repair method both change at the boundary.
Seasonal and post storm walks
Three walks in the year do different jobs, and adjusting the checklist for each one is more useful than repeating the same walk.
Autumn. Clear every drain, strainer, gutter and scupper before leaf fall, and check that nothing on the roof will come loose in winter wind. The aim is to get the roof into the wet season with its drainage working.
Spring. Look for what winter did. Split seams, damage from snow and ice, flashings that moved, sealant that cracked in the cold and any ponding that has appeared where there was none before.
After a storm. Start at the edges and the windward side, then check every lightweight item on the roof: coping, edge metal, flashing, panels, vents and anything mechanically fixed. Hail damage shows as bruising, fractured surfacing or dented metal, and it is easiest to see on soft metal such as vents and caps. Photograph everything on the same day, with the date visible, because the record matters if a claim follows.
After the walk
Photograph every defect with a reference point, rank each by urgency, and compare with the last visit. The comparison is the whole point: a defect that has not moved in two years is a different problem from one that has doubled.
Then convert the list into actions with owners and dates. Urgent items get a contractor. This year items go into the budget. Monitor items get re photographed next visit from the same position.
A checklist has limits, and it is worth naming them. It cannot tell you how much service life the membrane has left, and it cannot see water inside the roof. When an item comes back soft, stained or unexplained, that is the point to bring in the testing methods that find hidden moisture, and to ask for the findings in a written record. See what a good inspection report looks like, then compare it with what you were last sent.
Common questions
Can I inspect my own commercial roof?
You can walk your own roof and record what you see, provided access is safe and you use fall protection with a second person present.
- A checklist cannot judge remaining life or confirm hidden moisture
- Nor can it read a defect in the context of the whole system
- A quarterly owner walk catches blocked drains, debris, open panels and new punctures
- A professional inspection probes seams, tests suspect areas and writes a record
- That record is what stands up in a warranty or insurance claim
If the roof has no safe access, no fall protection or a fragile surface such as old fiber cement or a skylight run, do not go up. Photograph what you can from a window, a neighboring building or the ground, and hand the job to someone equipped for it.
How often should I run through a roof inspection checklist?
Twice a year is the working baseline for a commercial roof, once in spring and once in fall, plus a walk after any severe storm and after any trade has been on the roof.
- Quarterly is better with heavy equipment, frequent access or a leak history
- The fall walk clears drains and gutters before leaf fall
- The spring walk finds split seams, ice and snow damage, and flashings that moved
- Hail and wind damage is often invisible from the ground until the next heavy rain
- A dropped tool or a screw from any rooftop trade punctures a membrane
The trade access walk is the one most owners skip and the one that catches most fresh damage. Make a post work roof check part of your permit process and you will find that damage in days rather than seasons.
Does a metal roof need a different checklist?
Yes. A metal roof fails at its fasteners, seams and penetrations rather than in the middle of a panel, so the checklist shifts from membrane condition to hardware condition.
- Look for backed out fasteners, failed washers and opened seams
- Look for rust at cut edges and laps, and sealant gone hard at flashings
- Movement through temperature cycles works fasteners loose and elongates holes
- Check clips and sliding details are free, and nothing is screwed through a floating detail
- Check panel ends and anywhere water changes direction, where corrosion starts
Interior checks matter more on metal buildings than owners expect. Condensation on a poorly vented deck drips exactly like a leak, so confirm from inside whether water appears only in certain weather before chasing it outside.
What should I do with a completed checklist?
Turn it into a dated record and a short action list, then file it beside the previous walk so the two can be compared.
- Photograph every defect with a fixed reference point in frame
- Rank each item as urgent, this year or monitor
- One blocked drain is maintenance; the same drain every visit is a design problem
- A seam marked monitor last spring that has opened further is now a repair
- A ponding area that grows each year is telling you about deflection
Keep the records in one place, with dates, photographs and what was done. That file supports a warranty claim, satisfies an insurer asking for evidence of maintenance, and reassures a buyer or lender. A defect you recorded and chose to monitor is a decision.
Which checklist items get missed most often?
Drains, the perimeter and the area around rooftop equipment. The instinct is to look at the open field, which is the part least likely to fail.
- A strainer can look clear and still be blocked below the sump
- Edges and parapets sit at the boundary of the walk and get a passing glance
- Equipment areas need panels opened and condensate lines followed
- The visible underside of the deck shows rust and staining before a ceiling does
- Expansion joints move and fail quietly, and traffic damage hides under walkway pads
Water gets in where the roof meets something else, not in the middle. Lift a pad occasionally: what is underneath is often the reason a leak had no visible source.