Resource

Commercial Roof Inspection Checklist for Facilities Staff

Written for facilities staff rather than for a roofing crew. Take it up with a camera and a roof plan, work it in the same order every quarter, and stop where the list says stop.

Updated July 22, 2026

Before you set foot on the roof

A walkthrough by building staff between professional visits catches a great deal, and it is worth doing properly. It is also the point where people get hurt, so a few things get settled first. Confirm the access route is sound, whether that is a fixed ladder, an interior hatch or a stair. Do not go up alone, and make sure somebody knows you are there and when to expect you back.

Stay off the roof when it is wet, iced, or when lightning is anywhere in the area. A wet single-ply sheet is genuinely slippery. Skylights and translucent panels are not walking surfaces and they will not hold you, so treat every one as a hole with a lid on it. Keep back from the edge, especially where there is no parapet, and never lean over a roof edge to look at something.

Bring what makes the walk useful: a phone or camera, a marker or chalk, a tape measure, a notepad or a printed roof plan, and a bag for anything you pick up. Pick a fixed direction and keep it the same on every visit, since walking the roof the same way each time is what makes findings comparable from one season to the next.

Two people, a sound access route, and somebody who knows you are up there.
No wet surfaces, no ice, no lightning within range, no exceptions on any of the three.
Skylights and translucent panels are openings. Do not step on them or lean on their frames.
Camera, chalk, tape, roof plan and a debris bag. Photograph before you touch anything.

Drains, scuppers and gutters first

Start here every time, because this is where the cheapest problems live and where ignoring them gets expensive fastest. A blocked outlet raises the water line across an entire section and puts terminations under water they were never detailed to sit in.

Look at each outlet individually rather than glancing across the field. The strainer should be present, seated and clear. The clamping ring should be tight, with the membrane held evenly all the way around rather than pulled away on one side. The sump should sit below the surrounding surface so water actually reaches it. Scuppers should be open through their full depth, with the through-wall sleeve intact and the flashing sound where it enters the wall.

Then look for what the roof is telling you about drainage it is not achieving. Debris lines, silt rings and darker staining mark where water has stood, and those marks persist long after the water has gone. Note them on the plan, because they show the pattern between visits far better than a single wet day does.

Strainers present, seated and clear of leaves, seed, packaging and construction debris.
Clamping rings tight, with membrane gripped evenly around the full circumference.
Sumps set below the surrounding surface, not level with it or raised above it.
Scuppers open front to back, sleeves intact, wall flashing sound at the opening.
Overflow outlets present and clear, since they are the backup for everything above.
Gutters and downspouts on the perimeter clear, secure, and draining away from the wall.

Ponding evidence and where water is not going

Standing water is the largest single factor pushing a roof toward the bottom of its expected life, so the areas that hold it deserve specific attention. The rule of thumb worth working to is that a roof should be clear roughly two days after rain. Anything still wet beyond that is aging faster than the field around it.

You do not need to be there during a storm to find these areas. Dried ponds leave rings of silt, accumulated debris at the low edge, darker or discolored membrane, and often biological growth that keeps returning to the same footprint. Mark each one on the plan, estimate its extent, and photograph it from a consistent position so successive visits can be compared. Where a pond has appeared somewhere that used to drain, report it promptly rather than adding it to a list. Deflection in the deck, a crushed area of board under a heavy load, a blocked outlet or new equipment sitting in the flow path are the usual explanations, and two of those are structural.

The field: splits, blisters, punctures and raised fasteners

Walk the open areas in a consistent pattern and look at the surface rather than across it. Splits tend to be straight and to track something below them, usually an insulation joint or a lap in a lower layer, and what they indicate is an assembly flexing at a point that should be fixed. Any split is a reportable finding regardless of length.

Blisters are raised areas where layers have separated. A small firm one can be measured, photographed and watched. One that has gone soft underfoot, one that is growing between visits, or one sitting in a walking route needs attention before somebody puts a foot through it. Measure them with the tape rather than describing them as small or large, since a number is what makes the next visit meaningful.

Punctures are usually the work of another trade rather than the weather, and they are found by looking where people walk and where equipment gets serviced. On a mechanically fastened single-ply roof, also run a flat hand across the sheet in areas that read slightly raised. Fasteners migrate upward over years of movement, and a screw head bearing on a sheet from beneath will eventually wear a hole in it. None of that process is visible from above until the hole exists.

Splits: straight-line breaks, often over a joint below. Photograph, measure, report.
Blisters: measure the footprint, note firm or soft, and compare against the previous visit.
Punctures and abrasion: check walking routes, equipment access paths, and around every unit.
Raised fastener heads: sweep an open hand across suspect areas on mechanically fastened sheet.
Loose or displaced ballast and gravel: note bare areas, especially at corners and along edges.
Debris that holds moisture: pallets, packaging, cut zip ties, dropped screws and offcuts.

Seams and laps

Seams are the longest run of vulnerability on any low-slope roof, and a visual pass finds a useful share of what goes wrong with them. Follow the lap lines with your eyes and look for edges that have lifted, opened at a corner, or that show a dark line where dirt has worked into a partially open joint.

On welded thermoplastic, the edge should be tight and continuous. Wrinkles running into a lap, a lifted edge, or a fishmouth where the sheet has curled away are all findings. Probing a seam with a tool is a roofer's job and should be left to one. A properly welded lap will not open under a probe, which is the whole basis of the test, but an untrained hand gouges the membrane and can tear a lap that was marginal and still keeping water out.

On asphalt cap sheets, look for edges that have lifted or curled, areas where the cap has separated from the base, and bare compound along a lap line. Pay particular attention wherever a lap crosses a change in plane or runs into a detail, because that is where movement concentrates and where a marginal joint gives up first.

Flashings, terminations and edge metal

This is where most water actually enters a building, so it deserves more time than the field does. Every place the roof surface turns upward and stops is a detail somebody built by hand, and every one of them is checkable from a standing position.

Base flashings up walls and curbs should be continuous, adhered along their full height, and terminated at the top by a bar, a counterflashing or a reglet rather than by sealant alone. Sealant is a maintenance item and never a termination. Look at the corners specifically, since a corner formed by stretching material rather than by cutting and rebuilding it is the most common failure on the entire roof.

At the perimeter, edge metal should be flat, tight and continuous, with joints covered and no lifted sections. Coping on a parapet should be secure with its joints intact and its cover plates in place. Check the wall above a roof-to-wall transition too, because open mortar joints, failed sealant at a control joint and cracked masonry all deliver water that arrives inside looking exactly like a roof leak.

Base flashing adhered full height, with no bridging across the angle at the bottom.
Terminations made mechanically at the top. Sealant alone is not a termination.
Corners rebuilt rather than stretched. Look at every inside and outside corner.
Edge metal flat and continuous, joints covered, no lifted or oil-canned sections.
Coping secure, joints intact, cover plates present and fastened.
Masonry above a wall transition: open joints, failed sealant, cracks, missing caps.

Penetrations, curbs and rooftop equipment

Everything sticking through the roof is a potential entry point, and everything sitting on it is a potential source of damage. Take these as a group and walk them one at a time rather than scanning the area.

Pipe penetrations should be flashed with a proper boot or sleeve, clamped and sealed at the top, and standing clear of the surface. Pitch pans are the weakest common detail on any roof: the filler shrinks over time, pulls away from the pipe, and holds water in the resulting dish. Any pan sitting low, cracked, or separated from what passes through it is a finding. Equipment curbs should be tall enough that the base flashing terminates well above the surface, with the unit's own housing covering the top of the flashing.

Then look at what the equipment is doing to the roof. Condensate lines discharging directly onto the membrane wear a spot over years. Refrigerant lines and conduit lying on the sheet abrade it and trap dirt. Gas piping supported on scraps of wood, blocks or brick concentrates load and cuts. Missing or displaced walk pads leave the access route unprotected. Panels left off a unit, loose fasteners and hardware dropped and forgotten belong on the list as well, each with a photograph and a location.

Pipe boots intact, clamped at the top, sealed, and not split at the base.
Pitch pans full, not dished, not cracked, and not pulled away from the penetration.
Curb flashings terminated high and covered by the equipment housing above.
Condensate discharge directed to a drain rather than onto the membrane.
Lines and conduit carried on proper supports, never resting on the roof surface.
Walk pads present and following the route people actually use to reach each unit.
Loose hardware, offcuts, packaging and tools left behind by other trades, collected and bagged.

What to look for from inside the building

Half of a useful inspection happens below the roof, and it costs nothing but a walk. Ceiling stains, bubbled paint, rusted grid, corroded fasteners and efflorescence on interior masonry are all evidence, and they are frequently visible long before anyone reports a drip.

Where there is no ceiling, an exposed deck is the best diagnostic surface in the building. Rust streaks running along a flute, staining around a fastener, and discoloration spreading from a penetration all mark where water has been travelling. Note where each one sits in relation to the roof above, keeping in mind that water travels along a deck flute and appears wherever it finds an opening, which can be a long way from where it got in. Ask the people who occupy the space as well, and log what they tell you with dates: a tenant who mentions a stain that only shows up in a driving rain from one direction has given you a specific clue about a wall transition or a termination height.

Writing it down so it is worth something later

A walk that produces no record has limited value, because the whole point is comparison over time. Use the same roof plan every visit, mark each finding on it with a reference number, and photograph each one from a position you can return to. Date every photograph. Measure anything that could grow.

Separate what you corrected from what you found and left, and rank the open items by how soon they need attention. A roof with eight findings where two will admit water this season is a very different report than a roof with eight findings that are all cosmetic, and that distinction is what turns a list into a budget conversation.

Keep the file in one place and keep it in the same format from visit to visit. Over several years it becomes history: which areas keep reopening, how fast a blister is growing, whether last year's repair is still tight. That history is also what supports the conditions attached to whatever documentation came with the roof system on your building, since those conditions typically require periodic inspection, clear drainage and prompt repair by acceptable methods. Records are what demonstrate any of it happened.

Store it somewhere the next person can find it. Facilities staff change, and a file living on one laptop stops being history the day that laptop leaves.

One roof plan, reused every visit, with numbered findings marked on it.
Dated photographs taken from repeatable positions, close and wide for each item.
Measurements on anything that can grow, so the next visit compares numbers rather than adjectives.
Corrected items listed separately from open items, and open items ranked by urgency.
A running log of interior reports with dates, locations and weather conditions.

The things not to attempt yourself

A staff walkthrough is an observation exercise, and several of the tasks that look adjacent to it are not. Do not cut into the roof. Do not probe seams with a tool. Do not apply sealant, mastic, tape or spray products over anything, since a coating smeared across a failed detail hides the evidence, frequently traps water, and has to be removed before a proper repair can be made. Do not walk on a wet or frosted surface. Do not step on skylights, translucent panels or any equipment. Do not remove panels from operating equipment or attempt to move a unit. Do not go near a roof edge without proper fall protection, and do not use a roof hatch or ladder that does not feel sound.

The other half of that boundary is knowing what to escalate immediately rather than adding to a list. Active water entry, a split of any length, an exposed deck, a soft or spongy area underfoot, a new pond where the roof used to drain, or storm damage of any kind should be reported by phone as soon as you are back down.

Summary

Key takeaways

Two people, dry conditions, and a known access route. Skylights are openings, not walking surfaces.
Start at the drains every time. A blocked outlet raises the water line across a whole section.
Dried ponds leave silt rings and staining. You can map drainage problems on a clear day.
Most water enters at flashings, terminations and penetrations, not out in the open field.
Walk the interior too. An exposed deck shows rust and staining before anyone reports a drip.
Same plan, same route, dated photographs, measured findings. Comparison is the whole point.
No cutting, no probing, no sealant. Active water, splits, soft areas and storm damage get a call.

Keep reading

Next step

When the list runs past what a walk can settle

Some findings need somebody with a probe, a core cutter and a repair kit rather than a camera. If your walk turned up a split, a soft spot, an opening lap or a pond that was not there last year, send the photographs and the marked plan and we will come read them on the roof.

214-441-5352 Request an assessment

Questions from the walkthrough

How often should staff walk the roof?

Quarterly is a sensible rhythm for a staff walkthrough on most buildings, sitting between the professional inspections rather than replacing them. Add a walk after any significant storm, after any rooftop work by another trade, and any time a tenant reports something. Roofs with heavy equipment traffic or kitchen exhaust justify a shorter interval than that.

What is the single most valuable thing on this list?

Clearing the drains and confirming that water is actually reaching them. It requires no skill, it costs nothing, and blocked drainage causes more avoidable damage on low-slope roofs than any other single condition. If a walk only ever accomplishes one thing, make it that one.

Should we apply sealant to something small we find?

No. Sealant over a failed detail conceals the evidence a repair crew needs, often traps water behind it, and generally has to be cleaned off before a proper repair can be made, which adds labor. Photograph it, mark it on the plan, and report it. The only material a staff walk should apply to the roof is nothing at all.

Can we use a drone instead of walking it?

A drone is useful for overall condition, for mapping ponded areas after rain, and for reaching sections that are difficult to access safely. It will not find a raised fastener under the sheet, a soft blister, a bridged flashing corner, or a lap that has started to open. Treat aerial imagery as a supplement to a walk rather than a replacement for one.

We found something and we are not sure how serious it is. What now?

Photograph it, mark the location on the plan, and describe what you see rather than what you think it is. A dated photograph with a location is enough for a roofer to tell you whether it needs attention this week or at the next scheduled visit. Guessing at severity is the part to hand off, and describing it accurately is the part that helps.