In the Midwest, severe storms are not a matter of if—they are a matter of when. High winds, hail, heavy rain, and rapid temperature swings can all compromise a commercial flat roof. The real problem? Storm damage is rarely obvious right away. By the time you notice interior leaks, your building’s insulation may already be saturated, seams may have separated, and manufacturer warranties could be at severe risk.

For commercial building owners and property managers, knowing how to accurately identify and respond to storm damage is critical for protecting your asset and maintaining tight budgets. Our team of experienced professionals provide top-notch roofing services for businesses of all sizes. As business owners ourselves, we understand that your commercial property is one of your most valuable assets.

This guide breaks down exactly how severe weather impacts commercial roofing systems, what warning signs to look for, and how to take control before minor damage escalates into a major capital expense.

How Storms Affect Commercial Flat Roofs

Unlike steep-slope residential roofs, commercial flat and low-slope systems absorb the absolute full force of weather events. Storm damage on these facilities typically comes from a destructive combination of:

• Hail impact
• High wind uplift
• Wind-driven rain
• Flying debris
• Rapid atmospheric pressure changes

These powerful forces do not just affect the top surface. They impact the entire engineered roofing assembly, including the single-ply membrane, the rigid insulation, mechanical attachments, and flashing systems. Even if the roof appears completely fine from a ground-level vantage point, structural damage may already exist beneath the surface, waiting to cause massive disruptions to your daily operations.

Hail Damage: What It Looks Like on Different Systems

Hail damage remains one of the most common and misunderstood sources of commercial roof damage. Different materials absorb impact differently.

TPO and PVC Membranes

Single-ply systems like TPO roofing and PVC roofing are incredibly durable, but their impact resistance relies heavily on their age and the structural support beneath them.

• Newer membranes can generally tolerate hailstones up to 1¾ inches in diameter.
• Aging membranes lose plasticizers, becoming much more brittle over time.
• Hail damage often appears as subtle spiderweb cracks or circular fracture marks on the surface.

Even the smallest micro-cracks will expand with daily thermal movement, eventually pulling apart and leading to active leaks that disrupt your interior workspace.

EPDM (Rubber Roofing)

EPDM is highly flexible and offers exceptional impact resistance compared to many thermoplastic membranes.

• It can often withstand hailstones up to 2½ inches due to its rubberized elasticity.
• The membrane itself rarely cracks or splits strictly from surface impact.
• However, the primary concern is the hidden damage beneath the rubber surface.

If heavy hail compresses the rigid insulation below the EPDM, it can fracture the insulation facer and completely destroy the adhesive bond in fully adhered systems. Over time, this leads to a severe loss of adhesion, soft spots, drastically reduced wind uplift resistance, and premature membrane separation. Because the surface membrane looks intact, this costly damage is frequently missed without an expert consultation.

Built-Up Roofing (BUR)

BUR systems feature multiple layers of asphalt and reinforcing fabrics, typically topped with a layer of gravel surfacing.

• The gravel provides natural, durable impact resistance against most storms.
• Severe storms, however, can easily displace this gravel, exposing the vulnerable asphalt layers beneath.
• Once exposed, even small hail can bruise the waterproofing layers.

Gravel displacement also makes the overall roof highly vulnerable to wind scouring and ultraviolet (UV) degradation, significantly reducing the lifespan of the roof.

Wind Damage: The Silent Threat

While hail grabs the headlines, high winds frequently cause equal or greater damage to commercial facilities. High winds generate immense uplift pressures that can:

• Lift and fold back membrane edges
• Separate critical flashing at parapet walls
• Compromise heat-welded seams
• Dislodge edge metal and coping caps
• Loosen mechanical fasteners holding the insulation board

Wind damage rarely causes an immediate, pouring leak. Instead, it systematically weakens the attachment systems, drastically reducing the roof’s ability to resist the next passing storm. That is precisely why immediate post-storm inspections matter—even if hail was not a factor in your area.

Hidden Damage: Insulation and Delamination

One of the most expensive consequences of severe storms is the damage you absolutely cannot see. Large hail (2 inches or greater) or repeated impacts can completely crush rigid insulation boards. When this occurs:

• The insulation facer fractures and breaks apart.
• Adhesive bonds fail entirely.
• The protective membrane delaminates from the substrate.
• Thermal efficiency (R-value) decreases, causing energy bills to spike.
• Wind uplift resistance drops to dangerous levels.

These compromised areas often feel spongy underfoot but remain invisible from a ground-level view. Left unaddressed, they shorten roof life dramatically and require highly expensive, disruptive tear-offs.

What To Do After a Severe Storm

Taking highly organized, immediate action protects both your physical building and your insurance claim.

1. Perform a Safe Visual Check

From the ground or safe, secure access points, carefully look for:

• Dented edge metal or coping
• Damaged rooftop HVAC units
• Displaced gravel or debris
• Lifted or flapping membrane edges
  Never walk a potentially compromised commercial roof without the proper OSHA-compliant safety precautions.

2. Document Everything

Take high-quality photos of:

• Wide-angle roof views showing the overall condition
• Close-ups of visible cracks, punctures, or fractures
• HVAC units, vents, and metal components
• Parapet walls and perimeter edge details
  Insurance carriers rely heavily on precise, timely documentation to process your claims efficiently.

3. Schedule an Expert Consultation

Insurance adjusters are policy experts—they are not necessarily commercial roofing specialists. A professional roofing inspection identifies the highly technical issues:

• Micro-membrane fractures
• Microscopic seam separation
• Wind uplift damage and fastener back-out
• Hidden insulation compression
• Compromised drainage slopes

Having a technical expert involved guarantees nothing is overlooked, ensuring your budget remains intact. At All Seasons Roofing, we are your premier commercial roofing contractors! We use only the highest quality materials and our team of skilled roofers are trained to handle any job, big or small, cementing our reputation as a top commercial roofing company.