The Short Answer
Inspect a commercial roof at least twice a year, in spring after snowmelt and in fall before the first heavy snow, and again after any hail, high wind or heavy snow event and after other trades work on the roof. That matches NRCA's guidance and the owner maintenance terms in membrane warranties such as Mule-Hide's. Keep a written log and a report with photos for every visit.
Key Points
- NRCA recommends inspections at least twice a year, preferably spring and fall, plus additional inspections after severe weather.
- Membrane warranties put maintenance on the owner; Mule-Hide's owner guidelines call for spring and fall inspections, inspections after every major storm, and a written log.
- Grand Rapids averages 77.6 inches of snow a year under the 1991 to 2020 normals, so the fall visit is about getting drains and seams ready for a long winter.
- A useful report includes a roof plan, numbered photos, the condition of every system component, and repairs ranked by urgency.
- Anyone walking a low-slope roof near its edge needs fall protection under the federal standard MIOSHA adopts, so leave edge work to equipped crews.
Why Twice a Year Is the Baseline
The National Roofing Contractors Association recommends that building owners and managers inspect their roof systems at least twice a year, preferably in the spring and fall, with additional inspections after severe weather such as a tornado or hailstorm. NRCA's guidance also notes that most manufacturer warranties require roof systems to be properly maintained, and that warranty terms often limit the manufacturer's liability.
Manufacturers say the same in their own paperwork. Mule-Hide's building owner guidelines for its commercial single-ply systems state that the manufacturer's warranty is not a maintenance program, that inspecting and maintaining the roof is the building owner's responsibility, and that the system should be inspected at least twice a year, once in spring and once in fall, and after every major storm, by a Mule-Hide warranty eligible applicator or someone specially trained in roofing systems.
Twice a year is a floor, not a ceiling. Roofs with heavy rooftop equipment traffic, restaurant exhaust, tree cover or a history of leaks justify more frequent checks.
Fitting the Schedule to West Michigan Weather
The timing of the two main visits matters more in Michigan than in milder climates. Under NOAA's 1991 to 2020 climate normals for Grand Rapids, the airport averages 77.6 inches of snow a year, with about 20.8 inches in December, 22.6 in January and 17.2 in February, and measurable snowfall from October through April. It averages about 23.5 days a year with an inch or more of snow.
Freezing and thawing is the other half of the story. The same normals show about 133 days a year when the low drops below freezing, but only about 50 when the high stays below freezing. The difference, roughly 80 days, is when temperatures cross the freezing point, and that cycling works open seams, flashing terminations, sealants and the masonry coping on parapet walls.
Rain arrives heaviest in spring and fall. The monthly normals show about 4 inches in each of April, May and October, and the airport averages about 8 days a year with an inch or more of rain. Those are the storms that test drains and scuppers.
Lakeshore buildings and those in the lake-effect snowbelt see more snow and wind than the Grand Rapids airport; adjust the schedule for your site.
A Year of Commercial Roof Inspections
- Step 1
Spring, After Snowmelt (Late March to May)
Look for winter damage: punctures from snow removal or ice, open seams, flashing pulled away at parapets, cracked coping, damaged edge metal, and water stains inside. Schedule repairs for the summer season.
- Step 2
Summer, After Rooftop Trade Work
Check the roof after HVAC, electrical, solar or sign contractors have been up. Dropped screws, cut membrane and new penetrations made without the manufacturer's approval are common causes of new leaks.
- Step 3
Fall, After Leaf Drop and Before Heavy Snow (Late October to November)
Clear every drain, scupper and gutter, confirm overflows are open, close up seams and flashing issues found in spring, and check that rooftop units are sealed before winter.
- Step 4
After Any Severe Event
Inspect after hail, damaging wind, a heavy lake-effect snow or a rapid thaw. Document storm damage promptly for your insurer.
- Step 5
Before Key Dates
Inspect before a warranty expires, before a lease renewal that assigns roof costs, and before buying or selling a building.
What Each Inspection Should Cover
- Field membrane: punctures, blisters, splits, shrinkage, surface wear, and on coated roofs, coating thickness and wear.
- Seams and laps: open or fishmouthed seams, and adhesion at end laps.
- Flashings: base and counterflashing at walls, curbs and parapets, and termination bars and sealant.
- Penetrations: pipes, conduits, pitch pans and pipe supports, which Mule-Hide's guidelines treat as owner maintenance items for their exposed sealants.
- Drains, scuppers and gutters: clear, strainers in place, flashing intact, overflows open.
- Edge metal and coping: secure, sealed joints, no lifted sections that could let wind under the membrane.
- Rooftop equipment: unit curbs, condensate lines, access panels and service paths, plus walkway pads where traffic is regular.
- Ponding: locations and size of water still standing 48 hours after rain, which Mule-Hide's guidelines say good practice does not allow.
- Adjacent construction: masonry, mortar joints, sealants and stone that can leak and be blamed on the roof.
- Inside: ceiling stains, wet insulation at the deck, and anything tenants have reported since the last visit.
What a Good Inspection Report Includes
Keep every report together with a rooftop activity log of who went up, when and why. Mule-Hide's guidelines recommend exactly that log, and it is the record you will need if a warranty claim or a lease dispute comes up.
Roof plan
A simple drawing of the roof with drains, units, penetrations and problem areas marked and numbered.
Numbered, dated photos
One per finding, keyed to the roof plan, so anyone can find the spot again next season.
Condition by component
Membrane, seams, flashings, penetrations, drainage, edge metal and equipment, each rated or described.
Repairs ranked by urgency
What needs fixing now, what before winter, and what to watch, with the reason for each.
Moisture findings when warranted
Where leaks or soft areas suggest wet insulation, a moisture survey or core cuts tell you how far the water has spread. That decides between repair, coating restoration and replacement.
Repair vs coating restorationWarranty status
Manufacturer, warranty number and expiry, and any items the warranty treats as owner maintenance.
What Manufacturer Warranties Expect of Owners
Read the warranty on your roof before you need it. The terms in a Mule-Hide single-ply system warranty are a good example of what to look for. It excludes damage from the owner's or occupant's failure to use reasonable care in maintaining the roof, excludes conditions that prevent positive drainage, and excludes storm damage including peak wind gusts over 55 mph and hail.
It also sets a short clock. The owner must give written notice to Mule-Hide within ten days after discovering a leak, and notice to the contractor is not notice to Mule-Hide. Alterations or repairs on or through the roof, or objects attached to it, without Mule-Hide's prior written authorization can make the warranty cancelable.
Coated roofs carry their own duties. Mule-Hide's guidelines say warranties that include a coating may require periodic recoating at set intervals to keep coverage, at the owner's cost, and that exposed mastics and sealants are owner maintenance items. Build those dates into the inspection calendar.
Who Should Inspect, and Rooftop Safety
In-house staff can do a lot from inside the building and from a safe spot on the roof: watch for ceiling stains, check interior drains away from the edge, and keep the activity log. NRCA does not recommend that inexperienced property management staff walk roofs without the experience and equipment to do it safely, and Mule-Hide's guidelines ask for inspections by an eligible applicator or someone specially trained in roofing.
Safety rules point the same way. Michigan's general industry rule R 408.10202 adopts the federal walking-working surfaces standard, 29 CFR 1910 Subpart D. For work on low-slope roofs it requires guardrails, a safety net, travel restraint or personal fall arrest for anyone working within 6 feet of the edge, the same protection or a designated area from 6 to 15 feet, and a work rule keeping employees from going within 15 feet of the edge unprotected. Scuppers, edge metal and parapet flashing all sit in that zone.
How Stellar Handles Commercial Inspections
Our roof inspections are free and come with a written report and photos and a plain answer: repair, maintain, replace or leave it alone, and what each would cost. For storm damage on commercial roofs, Mihles Pena holds Haag certification for commercial roofs in his own name, and documents hail the way adjusters are trained to see it.
Stellar is a Mule-Hide contractor for flat and low-slope roofs and a GAF CoatingsPro contractor for silicone coating systems, and since 2012 we have roofed just over 4,000 homes and 1,600 commercial properties. Our commercial maintenance programs are built to catch problems at seams, drains and flashings before they become leaks and to keep manufacturer warranties in force with documented periodic inspection.
Commercial Roof Inspection Calendar for West Michigan
| When | Main Focus | Why Then |
|---|---|---|
| Late March to May | Winter damage, seams, flashing, coping, interior stains | After snowmelt; leaves summer to schedule repairs |
| After rooftop trade work | New penetrations, cuts, dropped fasteners | Other trades are a common cause of new leaks |
| Late October to November | Drains, scuppers, overflows, seams before winter | Leaves are down; snow season starts (about 7 inches in November on average) |
| After hail, high wind or heavy snow | Storm damage, punctures, lifted edges | Document promptly for insurance; manufacturer warranties exclude many storm events |
| Before warranty expiry or a sale | Full condition survey | Last chance to claim, or to price the roof into the deal |
Snow figure from NOAA 1991 to 2020 normals for Grand Rapids. Adjust for lakeshore and snowbelt sites.
Put Your Roof on a Schedule
Start with a free inspection and a written report with photos. We'll tell you what the roof needs now, what can wait, and how a maintenance program fits your warranty.
Related Guides
Commercial Roof Drains and Scuppers
Clogs, overflows, code requirements and repairs.
Learn MoreCommercial Roof Leak Action Plan
What to do in the first hour, and protecting the warranty.
Learn MorePonding Water on Flat Roofs
The 48-hour rule and repair options.
Learn MoreRoof Maintenance
Our maintenance service for homes and commercial buildings.
Learn MoreQuestions We Hear
How often should a commercial roof be inspected?
At least twice a year, in spring and fall, plus after severe weather. That is NRCA's recommendation and the schedule Mule-Hide's owner guidelines call for. Roofs with heavy equipment traffic, restaurant exhaust, overhanging trees or a leak history benefit from more frequent checks.
Does a commercial roof warranty require inspections?
Most require the owner to maintain the roof and exclude damage from a failure to do so. Mule-Hide's guidelines call for spring and fall inspections and after major storms, a written activity log, and prior written approval for alterations. Check your own warranty for its maintenance terms and its leak notice deadline, which can be as short as ten days.
Can our maintenance staff inspect the roof?
They can help, especially by watching for interior stains, checking interior drains well back from the edge and keeping the activity log. Work within 6 feet of a low-slope roof edge requires fall protection under the federal standard MIOSHA adopts. NRCA and manufacturers recommend inspections by trained roofing personnel.
What does a commercial roof inspection cost?
Ours are free and come with a written report, photos and a plain answer: repair, maintain, replace or leave it alone, and what each would cost. If the inspection points to further testing, such as a moisture survey, we explain why before anything else happens.
Should we inspect the roof after a heavy snow?
Yes, from the ground and inside first. Look for sagging, new ceiling cracks, doors that stick and water stains. If drifts are deep against parapets or rooftop units, have a roofer check drains and flashing once it is safe, and do not send staff onto a snow-covered roof edge.
What This Page Cites
- Tech Today: Routine preventative maintenance, Mark S. Graham, Professional Roofing, National Roofing Contractors Association, October 2013 (https://www.professionalroofing.net/Articles/Tech-Today--10-01-2013/2338), accessed October 2026
- Premium Single-Ply NDL System Warranty (Ver. 4.0) and Building Owner's Roof Care and Maintenance Guidelines (ver. 7), Mule-Hide Products Co., as filed with the City of Steamboat Springs (https://cityview.steamboatsprings.net/Portal/Permit/GetFile/35379), accessed October 2026
- U.S. Climate Normals 1991 to 2020, annual and seasonal normals, Grand Rapids Gerald R. Ford International Airport (USW00094860), NOAA National Centers for Environmental Information (https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-annualseasonal-1991-2020&stations=USW00094860&format=json&dataTypes=ANN-SNOW-NORMAL,ANN-PRCP-NORMAL,ANN-TMIN-AVGNDS-LSTH032,ANN-TMAX-AVGNDS-LSTH032,ANN-SNOW-AVGNDS-GE010TI,ANN-PRCP-AVGNDS-GE100HI), accessed October 2026
- U.S. Climate Normals 1991 to 2020, monthly normals, Grand Rapids Gerald R. Ford International Airport (USW00094860), NOAA National Centers for Environmental Information (https://www.ncei.noaa.gov/access/services/data/v1?dataset=normals-monthly-1991-2020&stations=USW00094860&format=json&dataTypes=MLY-SNOW-NORMAL,MLY-PRCP-NORMAL,MLY-TAVG-NORMAL), accessed October 2026
- Mich Admin Code R 408.10202, Adoption of federal standard (29 CFR 1910 Subpart D), Legal Information Institute, Cornell Law School (https://www.law.cornell.edu/regulations/michigan/Mich-Admin-Code-R-408-10202), accessed October 2026
- 29 CFR 1910.28(b)(13), Work on low-slope roofs, Electronic Code of Federal Regulations (https://www.ecfr.gov/current/title-29/subtitle-B/chapter-XVII/part-1910/subpart-D/section-1910.28), accessed October 2026