A porch or rear addition on a townhouse
Only where the roof is truly flat or nearly so. Your association's own documents come before any sheet, and the Sterling page explains who answers which question.
TPO roofs in Sterling, VA: what do the hail entries in NOAA's storm file say?
Hail makes Sterling owners ask whether a flat roof sheet can take it. The federal storm file has the dates and sizes for Sterling Park, Cascades and Countryside, and it is blunt about what it never recorded.
On which days did weather service reports put hail in Sterling, and how big?
We read NOAA's Storm Events Database files for 2016 through September 2026, kept the hail entries in Loudoun County and then the ones whose text names Sterling, Sterling Park, Cascades, Countryside or the weather service office in Sterling. Fourteen entries on five dates remain. The file is built from reports, so it is a list of what was reported, not a count of every hailstone.
- 2 June 2019
1.00 inch, Dulles 28 Centre.
- 28 July 2023
1.25 inches, with entries for Sterling, Sterling Park and Countryside.
- 7 and 8 September 2023
1.00 inch in Countryside and at the weather service office in Sterling on the 7th; 1.50 inches at the office and 1.25 in Sterling Park on the 8th, when the entry says hail covered the ground.
- 29 August 2024
2.50 inches on Ridgetop Circle, 2.30 on Terrie Drive in the Cascades area, golf ball size near Sterling Park, and entries at Cascades Parkway and Maries Road and at Algonkian Parkway and Countryside Boulevard.
The entries for 2016 to 2018, 2020 to 2022, 2025 and the first nine months of 2026 name none of those places. That is a statement about the file, and it does not rule out hail on your street on those days.
What the file never says
Not one of the fourteen entries mentions a roof
The 29 August 2024 entry for Ridgetop Circle reports 2.50 inch hail and "numerous vehicles had their windshields broken." The 8 September 2023 entry says wind-driven hail dented about half a dozen vehicles in the weather service parking lot. Both carry a dollar estimate in the damage field, and neither says which property it covers. The entries describe cars and sizes, so we make no claim that a roof in the area was damaged.
Which three conclusions do owners draw from hail news, and which survive the source?
Common assumption
Hail that breaks windshields has surely holed the flat roofs nearby.
What the source says
The entries speak of windshields and dented vehicles only. A roof can be hurt or unhurt by the same storm, and only someone on it can say.
Common assumption
A hail size from a data sheet settles whether TPO is the right sheet for Sterling.
What the source says
No neutral source we hold gives a hail size a TPO sheet withstands, so we print none. The 2021 International Building Code asks low-slope coverings to resist impact damage by ASTM D3746, ASTM D4272 or the foot-traffic test in FM 4470, as we read it, with no mention of hail.
Common assumption
If the sheet looks fine from the ground after a storm, nothing needs checking.
What the source says
The membrane trade group SPRI says low-slope roofs should be inspected after any major storm, with attention to loose metal at the perimeter, flashings around penetrations and clear drains.
When is TPO even the candidate for a building in Sterling?
TPO is a single-ply sheet listed as ASTM D6878 and classed among the heat-welded thermoplastics. That settles little by itself; the building decides.
A small office or flex building
The candidate list is wider. Ask for a written scope that names the membrane by its ASTM standard and states what happens at the edges and around equipment.
A garden-style apartment roof
The roof is a shared decision. Bring the 2024 and 2023 storm dates to the board so the discussion starts from inspection notes rather than from the hail size.
What should a Sterling owner put in the written scope after a hail day?
- The date and place of the hail you are worried about, so the roof's condition can be tied to a named storm.
- Photographs of the perimeter metal, the flashings around vents and units, and the drains, taken before anything is touched.
- The membrane named by its ASTM standard on the data sheet, not by a trade name.
- Whether the work is a repair, a coating, a recover or a replacement down to the deck, as the code defines each.
We give no lifespan for TPO: SPRI itself says no guarantee of length of life of any roofing product can be made. Our flat roof guide and the regional TPO guide cover the sheet itself.
Questions Sterling owners ask about hail and flat roofs
How many hail entries in NOAA's file name Sterling?
Fourteen, on five dates between June 2019 and August 2024, counting Sterling Park, Cascades, Countryside and the weather service office in Sterling. We read the files through September 2026.
What was the biggest hail reported near Sterling Park and Cascades?
The 29 August 2024 entry for Ridgetop Circle reports 2.50 inches, and another entry the same afternoon reports up to 2.30 inches in the Cascades area.
Does the file say hail damaged roofs in Sterling?
No. The entries describe sizes, broken windshields and dented vehicles. The damage estimates in two entries are not tied to any roof.
Is Loudoun's snow load a reason to choose or avoid TPO?
Loudoun's code page lists 30 psf, and the Sterling page carries it. We hold no neutral document that ranks membranes by that number, so it belongs in the structural conversation, not the material one.
Should I call after hail even if I see no leak?
The trade group SPRI advises inspecting low-slope roofs after any major storm. A call lets us ask what you saw and whether a closer look is worthwhile.
Can I rely on a hail size printed on a TPO data sheet?
We do not quote one, and we hold no neutral source for it. Ask which test the number comes from and which ASTM standard names the sheet.
Which TPO pages sit nearby?
See TPO roofs in Ashburn and TPO roofs in Leesburg, both in Loudoun, or the Sterling guides for EPDM, metal and PVC. All of our service areas are listed together.
Sources used (checked October 16, 2026):
Talk through the next step
Tell us the building, the storm date and what you saw
Give us the street, the date of the hail you remember and what the roof surface looks like from where you can safely see it. A short phone call comes first.
Book a free 15-minute phone consultation
(703) 712-1506
9220 Topaz St, Fairfax, VA 22031
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