Summer heat and sudden storms trigger predictable, costly damage without proactive commercial roof maintenance. From membrane blistering to clogged drains, flat roofs take the brunt of summer weather. Catching a minor drainage issue today prevents severe structural damage tomorrow.
This guide outlines how heat impacts your facility, what to check after severe weather, and how to catch small issues early. Use these practical insights to protect your building, maintain your warranty, and keep your budget on track all summer long.
Summer is hard on commercial roofs because heat, UV, and daily temperature swings stress the membrane, seams, and flashing at the same time. Flat roofs are exposed to the sun all day, which causes the roof surface to heat up more than the surrounding air.
During the day, the roof heats up and expands. At night, it cools and contracts. Over a summer of these cycles, the movement can weaken seams, laps, and flashing where the membrane meets walls, curbs, and edges. UV exposure breaks down the membrane surface over time, causing chalking, crazing, or brittleness. Heat also softens adhesives and sealants and speeds their aging, so weak bonds that held through spring often open in July and August.
Low-slope roofs have no pitch to shed heat or water quickly, so they absorb more of the sun’s heat and retain water longer than steep roofs. They also carry rooftop HVAC units, which work hardest in summer and require more service technicians on the roof. Every extra trip adds foot traffic, dropped tools, and the chance of a puncture.
Ponding water is the most expensive problem on a commercial flat roof during the summer. This issue usually comes from a poor slope or drainage. The National Roofing Contractors Association (NRCA) considers a roof properly drained when no water remains 48 hours after a rain under conditions that allow drying. If water remains longer, it is a defect, not just a cosmetic issue.
Most commercial flat roofs use one of three flat roof drainage systems, or a combination:
| System | How it works | Best fit | Watch for |
|---|---|---|---|
| Internal drains | Drains set at low points across the roof carry water down through pipes inside the building, usually with strainers to catch debris. | Large roofs that collect water toward the center | Clogged strainers; higher installation cost than other options |
| Scuppers | Openings in the parapet or roof edge push water off the side of the building, often into a collector box and downspout. | Perimeter drainage and overflow backup for internal drains | Works best with tapered insulation, directing water to them; debris blocks them quickly |
| Gutters and downspouts | Gutters along the roof edge collect runoff and direct it away from the building. | Smaller buildings and roofs without parapets | Need regular cleaning to keep flowing; can be overwhelmed in heavy storms |
The right roofing system depends on the roof’s size, slope, and the building’s design. For any changes, work with a roofing professional. If you are building a new structure, consult with the design team.
Standing water adds dead load to your roof structure, breaks down the membrane, and feeds leaks at any seam or penetration. Many commercial roof warranties require positive drainage, so chronic ponding can also compromise your coverage.
The International Building Code requires a minimum slope of 1/4 inch per foot for membrane roofs. Tapered insulation is the standard way to correct low spots without rebuilding the deck.
Summer storms make all of this worse. A drain half-blocked by leaves or debris cannot handle a short, heavy downpour, and the water backs up across the roof. You can patch small seam leaks with roof sealants as a stopgap, but the lasting fix is clearing the drain path and correcting the slope.
The top summer commercial roof problems are blistering, open seams, failing flashing, punctures, and clogged drains. Each one starts small and becomes a leak, and most are visible during a walk on the roof.
Blisters form when trapped moisture or air expands under the roof membrane in hot weather. You can monitor a few small, intact blisters, but if they crack or keep growing, water can get in. The seams on TPO, EPDM, and PVC roofs are another weak spot. Thermal movement and aging adhesives can open laps, especially at corners and edges.
Flashing around vents, pipes, skylights, and HVAC curbs gets a lot of foot traffic. Technicians servicing air conditioning units can accidentally puncture the roof membrane with their tools or panels. Leaves, packaging, and storm debris can build up around equipment and drains, trapping moisture against the surface.
Use this checklist on a summer roof walk:
| Issue | What to look for | Why it matters |
|---|---|---|
| Blistering | Raised bubbles, cracked or split blisters | Split blisters let water under the membrane |
| Seam separation | Lifted edges, open laps, gaps at corners | The most common entry point for leaks |
| Flashing failure | Gaps, cracks, or loose metal at curbs, walls, and penetrations | Water follows the gap straight into the building |
| Punctures | Cuts, holes, or dents near HVAC units and walkways | Small holes saturate insulation before a leak shows inside |
| Clogged drains and scuppers | Debris at strainers, standing water nearby | Blocked drains lead to ponding and overload |
| Interior warning signs | Ceiling tile stains, musty odors, drips near walls | The roof has already let water in |
If water is already coming into the building, treat it as an emergency roof repair and protect people, equipment, and inventory first.
Schedule a trusted consultation! Find your local Storm Guard Roofing team to get your commercial roof checked before the next storm.
Summer storms damage commercial roofs mainly through hail and strong winds. Often, this damage isn’t visible from the ground. After a significant storm, check your roof within a few days.
Hail can damage roofing by bruising or fracturing a membrane, cracking the insulation board beneath it, and denting metal flashing and rooftop units. Wind mostly affects the edges and corners, where it can lift the membrane, loosen the edge metal, and raise the coping. Learn the signs of hail damage so you know what a new impact looks like.
Follow this step-by-step sequence right after severe weather passes to catch hidden damage before it turns into a major leak.
Address active leaks immediately with emergency service, while stable damage can be scheduled.
Storm Guard Roofing inspects your roof and provides photo-documented reports that you can share with your insurer. You can check your own policy with your carrier. Review our storm and hail damage roof repair guide to learn more.
A strong commercial roof maintenance plan combines regular professional inspections, clear drains, and a detailed service log. NRCA recommends inspecting your roof at least twice a year, ideally in spring and fall. Additionally, it is advisable to perform inspections after severe weather such as a hailstorm.
Follow this year-round routine to catch minor issues early and protect your building through every season:
Record each inspection, repair, and contractor visit with dates and photos. Clear maintenance records track your roof’s condition over time and keep your manufacturer’s warranty valid.
Preventive maintenance lowers the total cost of owning a roof because small repairs are cheaper than leaks, interior damage, and early replacement. A professional commercial roof inspection covers the membrane, seams, flashing, drainage, and rooftop equipment and gives you a prioritized list of repairs to plan and budget for.
Schedule a trusted consultation! Find your local Storm Guard Roofing team on our locations page and protect your building before the next summer storm.
The most common problems are membrane blistering, seams separating due to heat, ponding water from poor drainage, clogged drains after storms, UV wear on the membrane, and punctures from roof traffic. Most are preventable with a summer inspection and regular drain clearing.
Ponding is caused by inadequate slope, sagging insulation or deck, and clogged or undersized drains and scuppers. Water that remains for 48 hours after rain indicates a drainage defect. It adds dead load, breaks down the membrane, and can affect your warranty, so correct it promptly.
At least twice a year, in spring and fall, and again after any major storm. Regular inspections, drain clearing, and a documented maintenance log catch small failures before they become leaks and support warranty and insurance records.
It depends on roof size, slope, and building design. Internal drains suit large roofs with central low points; scuppers handle perimeter drainage and overflow; and gutters suit smaller buildings. A roofing professional can confirm the best option for your building.
Yes. Daily heating and cooling cause the membrane to expand and contract, stressing seams and flashing, while UV exposure breaks down the surface over time. Heat also softens adhesives and speeds aging, which is why summer often exposes a roof’s weak points.
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