Storm and Hail Damage ยท Houston, Texas
Commercial Roof Storm and Hail Damage in Houston
After a storm, the questions are always the same: is the roof damaged, how bad is it, and what does the insurer or manufacturer need to see. This guide explains what wind and hail actually do to commercial roof systems, how damage is assessed and documented, and how warranties treat it, for owners across Houston and the Bay Area.
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The short answer
Storm and Hail Damage: what Houston owners should know.
Storm damage to a commercial roof is physical damage caused by a specific weather event: wind that lifts edge metal, coping, flashings or membrane, and hail that fractures membranes, dents metal or crushes insulation and cover board. Engineers at Haag describe functional damage as damage that reduces the roof's weather resistance or expected service life. Hail one inch or larger is severe by NWS criteria, but smaller hail can damage aged or brittle roofs.
Mammoth Services performs post-storm roof assessments in Houston and the Bay Area, sets temporary protection, and documents damage with photos, core cuts and written findings your insurer and manufacturer can review. Coverage decisions belong to them. Call (832) 416-1566.
Houston storm record
Why Houston roofs take repeated storm hits
Wind, flood rain and hail all show up in the recent record. Each one damages roofs differently.
Hurricane Beryl, July 8, 2024
Landfall near Matagorda at 4 a.m. as a Category 1. NWS recorded unofficial gusts of 84 mph at Hobby and 83 mph at IAH, with more than 5 inches of rain at both.
Derecho, May 16, 2024
NWS Houston described a swath of 100+ mph winds through the Houston metro with widespread damage. Straight-line wind peels edges and throws debris.
Southeast Harris tornado, January 24, 2023
An EF3 tornado with estimated peak winds of 140 mph crossed parts of southeast Houston, Pasadena, Deer Park and Baytown, according to the NWS preliminary survey.
Hurricane Harvey, 2017
The NWS Houston office measured 43.38 inches of rain, which NWS called the highest 5-day total on record for any major U.S. city. Rain like that finds every weak flashing.
Hail is part of the record
NWS lists golf ball hail up to 1.75 inches in Houston on October 22, 2008, hail up to 3 inches near Hooks Airport on May 4, 2006, and hail up to 4.5 inches in Hitchcock on April 2, 2013.
Sources: NWS, Beryl, NWS, May 2024 summary, NWS, SE Harris tornado, NWS, 2010s tropical cyclones, NWS Houston, severe thunderstorms.
By roof system
What wind and hail do to commercial roofs
Damage depends on hail size and hardness, wind speed, and the roof's type, age and condition. Haag notes base flashing is often damaged first.
| Roof system | Hail damage | Wind damage |
|---|---|---|
| TPO and PVC | Crescent fractures, often at fastener plates, from 1/16 inch to 1 inch long; dented insulation; aged PVC can turn brittle | Lifted perimeter and corners, torn seams, membrane billowing at failed attachment |
| Modified bitumen | Punctures, tears, displaced granules; Professional Roofing reports damage to APP and SBS from about 1.5 inch hail | Lifted laps and edges, torn base flashing |
| Built-up (BUR) | Punctures, tears, bruising; soft spots from broken reinforcement; smooth surfaces more vulnerable than gravel | Gravel scour, lifted edges, blown-off gravel stops |
| Metal | Dents, ruptured panels, disengaged lap elements; field-applied paint may be disrupted | Lifted trim, ridge and eave flashing, fastener pull-through |
| Edges and equipment | Damaged HVAC fins, skylights and vents | Coping and edge metal loss, displaced curbs and flashings, debris punctures |
Sources: Morrison, Haag Engineering, Professional Roofing (2009), Vitiello, Professional Roofing (2007), IBHS commercial roofs best practices.
Hail size
What size hail damages a commercial roof?
There is no single number. Size matters, but so do hardness, roof age and what sits under the membrane.
Starting points
NWS classifies a thunderstorm as severe when it produces hail one inch in diameter or larger. A 2007 Professional Roofing article on hail cites 3/4 inch as a commonly used minimum threshold for property damage, and reports PVC fractures from hail of about 3/4 to 1 1/2 inches.
Condition changes the answer
Haag Engineering's Scott Morrison writes that weathered materials become more brittle and resist impact less, that thicker membranes and gravel surfacing generally resist hail better, and that the stiffer the substrate, the more hail-resistant the membrane. A membrane over a cover board fares better than the same membrane over soft insulation.
What counts as storm damage
Morrison draws a useful line: a roof is functionally damaged when its weather resistance is diminished or its expected service life is reduced. Cosmetic marks that do neither may not require repair. That distinction is what a good assessment documents, section by section.
Rated resistance
FM Global's data sheet 1-34 sorts the U.S. into moderate, severe and very severe hail zones, with a large portion of Texas in the very severe zone, per NRCA's Professional Roofing. IBHS recommends a Severe Hail rating for hail-prone areas.
Sources: NWS Houston, Professional Roofing (2007), Professional Roofing (2009), Professional Roofing (2018), IBHS.
After the storm
Post-storm roof assessment, step by step
Safety and water control first, then documentation before permanent repairs.
Check from inside first
Find active leaks and wet ceiling tiles, protect what is below, and note times and locations.
Walk every roof section
Inspect perimeter edge metal and coping, corners, seams, base flashings, drains, skylights and rooftop units. Wind damage concentrates at edges and corners.
Look closer for hail
Check the membrane for fractures, especially at fastener plates, test for soft spots, and look at metal for dents and HVAC fins for impact marks.
Confirm what is under the surface
Core cuts show whether insulation or cover board is crushed or wet. A moisture survey maps saturation across the roof.
Stabilize
Dry-in openings and secure loose edge metal to stop further damage. TDI notes policies may require reasonable temporary repairs and may pay for them.
Report in writing
Deliver photos, core cut results and written findings by roof section, separating storm damage from pre-existing wear.
See TDI claim tips and TDI hail claim tips.
Documentation
Documenting storm damage for your insurer
Claims are decided by the insurer, not the roofer. Good documentation helps the adjuster see what happened. This is general information, not insurance or legal advice; check your policy with your agent, insurer or attorney.
Report quickly
TDI's hail guidance says to file a claim quickly. Policies often set notice requirements, so check yours for the exact terms.
- Note the storm date and time
- Record when damage was found
Photos before repairs
TDI advises taking photos or video of the damage before making repairs, and not making permanent repairs until the adjuster has inspected.
- Wide shots for location, close-ups for detail
- Interior damage tied to roof areas
- Keep damaged materials until told otherwise
Core cuts and findings
Surface photos do not show crushed or wet insulation. Core cuts and written findings by section give the adjuster evidence of what sits under the membrane.
- Location map of cores
- Measured hail marks and fractures
Keep every receipt
TDI says to keep all receipts for repairs, including temporary ones. Your contractor and the adjuster can also discuss repair or replacement costs directly.
- Temporary protection invoices
- Emergency labor and materials
Coastal properties may be insured through TWIA, which covers all of Galveston County and parts of Harris County east of Highway 146 (TWIA). For windstorm inspection and code rules see Texas windstorm requirements for commercial roofs.
Warranty
Does a roof warranty cover hail or wind damage?
Usually not by default. Manufacturer guarantees cover the roof's performance, and most exclude storms above stated limits unless coverage was added.
Standard exclusions
GAF's EverGuard Diamond Pledge NDL specimen excludes winds over 55 mph and hail, hurricanes and tornadoes unless covered by an addendum. GAF's coverage guide says its guarantees do not provide hail coverage as standard.
- Base wind coverage up to 55 mph
- No hail coverage by default
Purchased coverage
GAF's single-ply guide lists optional hail coverage of 1, 2 or 3 inches and higher wind speed limits for select systems only, with advance written GAF approval. Some options require an FM VSH hail rated assembly with a specified cover board.
- Must be specified before the job
- Not every system qualifies
What hail coverage repairs
GAF's hail coverage specimen says GAF repairs the punctured membrane and is not responsible for the deck or other system components. Other damage may fall to your property policy.
- Membrane repair only
- Read the addendum's diameter limit
Notice and emergency repairs
GAF requires written leak notice to GAF within 30 days, separate from telling the contractor. Reasonable emergency temporary repairs to limit damage are allowed at the owner's expense.
- Notify GAF directly
- Keep temporary repairs reasonable
Sources: GAF Diamond Pledge NDL specimen, GAF Diamond Pledge hail coverage specimen, GAF single-ply guarantee coverage guide. Eligibility, terms and coverage are set by GAF and depend on the roof system and project.
Service area
Storm and hail damage response across Houston and the Bay Area
Storm exposure is not the same across the region. Distance to the bay, insurance setup and building type change the assessment.
Houston, TX
The 2024 derecho's 100+ mph swath and Beryl's 84 mph Hobby gust both hit the city, so check edges, coping and rooftop units after every event. Commercial roofing in Houston.
Webster, TX
Medical and professional buildings need fast dry-in after a storm, plus documentation that ties each interior leak to a roof location. Webster commercial roof repair.
Clear Lake, Houston
Large flat roofs on office and technical campuses near the NASA Johnson Space Center hide hail damage under the surface, which makes core cuts essential. Clear Lake flat roof repair.
Nassau Bay, TX
Buildings facing Clear Lake take wind with little to slow it, so lifted perimeter metal is often the first thing we document. Nassau Bay storm response.
Seabrook, TX
Seabrook is inside the TWIA designated area, so windstorm coverage, inspection paperwork and roof documentation should line up from the first visit. Seabrook commercial roof repair.
League City, TX
All of Galveston County is TWIA designated, and League City's retail centers often need a storm-damaged roof scoped as repair, recoat or replacement. League City replacement and coating.
La Marque, TX
Industrial and warehouse roofs near Hitchcock sit close to where NWS logged 4.5 inch hail in 2013, so metal and older built-up roofs deserve a full hail check. La Marque commercial roof repair.
Dickinson, TX
Bay storms push heavy rain sideways into flashings and laps here, so wind-driven leaks need to be separated from long-term wear in the findings. Dickinson commercial roof repair.
Santa Fe, TX
Schools, churches and metal buildings in this Galveston County city often need dent and fastener surveys after hail, plus clear photos for the claim file. Santa Fe commercial roof repair.
Pasadena, TX
Parts of Pasadena are in the TWIA area and the 2023 EF3 tornado crossed the city; plants and warehouses need storm findings that also cover rooftop equipment. Pasadena commercial roof repair.
TWIA designated area per TWIA.
Questions
Storm and Hail Damage: direct answers.
If your question is not here, call Mammoth Services at (832) 416-1566.
- 01
What is considered storm damage to a commercial roof?
Storm damage is physical damage caused by a specific weather event, such as wind lifting edge metal or membrane, or hail fracturing the membrane or crushing insulation. Haag Engineering describes functional damage as damage that reduces the roof's weather resistance or expected service life. Normal aging and wear are not storm damage. Whether damage is covered is decided by your insurer under your policy.
- 02
What size hail damages a commercial roof?
It depends on the roof. NWS calls hail one inch or larger severe. Professional Roofing has reported PVC fractures from hail of about 3/4 to 1 1/2 inches and modified bitumen damage from about 1 1/2 inch hail. Older, brittle membranes and roofs over soft insulation are more vulnerable, while cover boards and thicker membranes resist better.
- 03
How do I know if my flat roof has hail damage?
Hail damage on flat roofs is often hard to see. Look for fractures on single-ply membranes, especially at fastener plates, soft spots or bruising on built-up and modified bitumen roofs, dented metal and damaged HVAC fins. Core cuts confirm whether insulation or cover board underneath is crushed or wet. A professional assessment documents it section by section.
- 04
Does a roof warranty cover hail damage?
Usually not by default. GAF's Diamond Pledge specimen excludes hail and winds over 55 mph unless an addendum covers them. GAF sells hail coverage of 1, 2 or 3 inches for select systems with advance approval, and even then it covers membrane repair, not the deck or other components. Eligibility and terms are set by GAF.
- 05
Should I make temporary repairs before the adjuster comes?
Generally yes, to prevent further damage. TDI notes policies may require reasonable temporary repairs and may pay for them, and advises photographing damage first and keeping receipts. TDI also says not to make permanent repairs until the adjuster has inspected. Check your policy and talk with your agent or insurer about specifics.
- 06
Who can assess storm damage on my commercial roof in Houston?
Mammoth Services performs post-storm assessments across Houston and the Bay Area, sets temporary protection and provides photos, core cut results and written findings by roof section. We repair roofs we did not install. Book at our contact page or call (832) 416-1566.
Sources
- NWS Houston/Galveston: Hurricane Beryl 2024
- NWS Houston/Galveston: May 2024 Regional Climate Summary
- NWS Houston/Galveston: Southeast Harris County tornado summary
- NWS Houston/Galveston: Upper Texas Coast tropical cyclones in the 2010s
- NWS Houston/Galveston: Spring weather safety, thunderstorms
- Professional Roofing: Holy hail! (Morrison, Haag Engineering, 2009)
- Professional Roofing: Standing up to hail (Vitiello, 2007)
- Professional Roofing: Designing for hail resistance (Graham, 2018)
- IBHS: Commercial Roofs Best Practices
- GAF: EverGuard Diamond Pledge NDL Roof Guarantee specimen
- GAF: EverGuard Diamond Pledge NDL Roof Guarantee with hail coverage specimen
- GAF: Quick reference guide, guarantee coverage for single-ply systems
- Texas Department of Insurance: Tips for filing a claim
- Texas Department of Insurance: Hail damage? Tips to file an insurance claim
- TWIA: Coverage area / designated catastrophe area
This page is general information for commercial property owners, not legal, insurance or engineering advice. Warranty eligibility and terms are set by the manufacturer.
Next step
Talk to Mammoth about your roof.
Call Mammoth Services at (832) 416-1566, or book a roof assessment and tell us about your building. For planned work, book a roof assessment call.