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PVC roofing in Sterling, VA: hail on the record, impact in the documents
Sterling has hail rows in the federal storm database, and a PVC membrane is a thin sheet. The question this page works through is how those two facts meet. We counted NOAA hail rows for Loudoun County by place label and by size, then read what a federal PVC specification, the Virginia residential code and the IBHS hail page say about impact. The answer is mostly in what they leave out.
- 4 NOAA hail rows carry the label Sterling, largest 1.25 inch
- 12 hail rows name Sterling in label or narrative, largest 2.50 inch
- The federal PVC spec uses the word hail once, about cover board
The finding in one box
Sterling has hail on the NOAA record. None of the four documents read here, the federal PVC specification, the Virginia residential code, the IBHS hail page or NOAA itself, gives a hail or impact rating for a PVC membrane. The specification points at thickness and at the board beneath the sheet, and that is the whole of what is written.
That is a PVC-specific point. Our Sterling hub already tabulates the weather rows for the area, and this page recounts the hail rows only, cut by size, date and place label. For the material itself, see the general PVC roofing page.
Why the label changes the count
Label says Sterling
Four rows: 1.00 inch on June 2, 2019, 1.00 inch on July 28, 2023, 1.25 inch on September 8, 2023 and 1.00 inch on August 29, 2024. The largest is 1.25 inch.
Narrative says Sterling
Twelve rows. Eight carry another label: five Broad Run Farms and three Dulles Intl Arpt. The largest is 2.50 inches, on Ridgetop Circle, with numerous vehicles reported with broken windshields.
NOAA places each row at a nearby reference point, so the label tells you where the database put the row, not where the stone fell. Anyone quoting hail figures for a town should say which cut they used. Counting by label alone would give Sterling a top size of 1.25 inch, and counting by narrative gives 2.50. The narratives report no roof damage in either cut.
Loudoun hail rows by size
NOAA's Storm Events details files for 2016 through 2026 hold 56 hail rows in the Loudoun County zone, on 18 separate dates. NOAA records hail size in inches to the hundredth. Grouped by size, the 56 rows look like this.
| Reported size | Rows | Share of 56 |
|---|---|---|
| Under 1.00 inch | 3 | 5.4% |
| 1.00 inch | 36 | 64.3% |
| 1.25 inch | 3 | 5.4% |
| 1.50 inch | 7 | 12.5% |
| 1.75 inch | 4 | 7.1% |
| 2.30, 2.50 and 3.00 inch | 3 | 5.4% |
Source: NOAA National Centers for Environmental Information, Storm Events Database, Loudoun County zone rows; counts and shares are ours. Rows are reports, not separate storms.
What each PVC document says about impact
- UFGS 07 54 19, thickness
- The August 2023 federal guide specification sets reinforced PVC at a minimum polymer thickness of 2.03 mm (0.08 inch). A 2.4 mm (0.096 inch) sheet is named for regular heavy traffic or regular extreme wind that can carry airborne debris, or a combination adhered and protected system for high wind.
- UFGS 07 54 19, hail
- The one hail sentence is a designer note that glass mat and moisture resistant gypsum board used as an overlayment can improve wind, impact and hail resistance. The specification states no stone size or impact class for the membrane.
- UFGS 07 54 19, standards
- The membrane follows ASTM D4434 or D6754, and the roof is Class A under ASTM E108, FM 4470 or UL 790, with fasteners and plates meeting FM 4470. FM Global's own pages refused automated access today, so what FM 4470 tests for hail is not stated here.
- Virginia Residential Code R905.13
- Thermoplastic single-ply roofs need a slope of at least 1/4 unit in 12, must follow ASTM D4434, D6754 or D6878 and are installed to the manufacturer's instructions. The section does not use the words hail or impact.
- IBHS hail page
- The Hail Lab fires lab-made stones from a pressurized cannon at roofing products. The list names asphalt shingles, synthetic composite shingles, low-slope metal roofing, photovoltaic panels and cladding. A PVC membrane study is not listed.
"to impart improved wind, impact, and hail resistance"
UFGS 07 54 19 (August 2023), designer note on gypsum roof boardThe same specification adds a compatibility note: PVC is not to touch asphalt, coal tar pitch or petroleum-based products, and it is not adhered directly to polystyrene, perlite or standard wood fiber insulation. Those layers matter to impact too, because the sheet sits on whatever is below it.
Sterling hail days, in order
Twelve of the 56 rows name Sterling in the place label or the narrative. They fall on five dates.
- June 2, 2019Quarter size hail, 1.00 inch, reported at the Dulles 28 Centre.
- July 28, 2023Quarter size hail reported in Sterling Park, with a second 1.00 inch row filed under Broad Run Farms.
- September 7, 2023Quarter size hail observed at the National Weather Service office in Sterling.
- September 8, 2023Half dollar size hail in Sterling Park, and at the same office a later round that the narrative puts between quarter and ping pong ball size.
- August 29, 2024Six rows name Sterling, from 1.00 inch up to golf ball size near Sterling Park, 2.30 inches in the Cascades area and 2.50 inches on Ridgetop Circle.
Four of the five dates fall in 2023 and 2024, and the largest stones belong to a single afternoon.
Impact items to put in writing
- The membrane thickness, in inches or millimeters, as printed on the manufacturer's data sheet.
- Whether any cover board sits under the sheet, which board, and who chose it.
- The insulation type under the membrane and the manufacturer's statement that it is compatible with PVC.
- Whether the manufacturer publishes any hail or impact test for this exact assembly, and the name of the test.
- Which edges and walkways get thicker sheet or walk tread.
- Photos of the roof before work, so a later hail inspection has something to compare against.
- For an association or condominium building, which documents say who approves the work.
Roofers of Arlington installs, repairs and replaces roofs, including flat and metal systems. Book a phone consultation to talk through a Sterling PVC roof: we would ask the address, the building type, what the surface looks like from the ground and which of the items above you already hold.
See roof replacement, commercial roofing, roofing insurance and the full list of services. To compare coverings, open materials, or return to the Sterling guide.
Pages opened on October 24, 2026
Questions people ask
Is there a hail rating for PVC roofing in the Virginia residential code?
Section R905.13 of the 2021 Virginia Residential Code covers thermoplastic single-ply roofs. It sets a minimum slope, names ASTM D4434, D6754 or D6878 as the material standards and requires installation to the manufacturer's instructions. The section has no hail or impact wording, so the code leaves that question to product literature.
Does the federal PVC specification give a hail size a membrane must survive?
The Department of Defense guide specification UFGS 07 54 19 sets a minimum membrane thickness of 0.08 inch and a thicker 0.096 inch option for heavy traffic or extreme wind with debris. It uses the word hail once, in a note about cover board. It states no hailstone size or impact class for the membrane itself.
How many NOAA hail records carry the label Sterling?
Four, in the Loudoun County rows for 2016 through 2026 that we counted on October 24, 2026. They fall on June 2, 2019, July 28, 2023, September 8, 2023 and August 29, 2024. Sizes run from 1.00 to 1.25 inch. More rows name Sterling in the narrative but carry other labels.
What was the largest hail reported in Sterling in the NOAA data?
Event 1207695, on August 29, 2024, records hail of 2.50 inches on Ridgetop Circle in Sterling, with numerous vehicle windshields broken. NOAA files it under the label Broad Run Farms, which is why a search on the label Sterling alone does not find it. The narrative reports no roof damage.
Does IBHS have hail test results for PVC membranes?
Its hail research page lists Hail Lab studies on asphalt shingles, synthetic composite shingles, low-slope metal roofing, photovoltaic panels and cladding. A PVC or other single-ply membrane study is not on that list. IBHS does publish a page on telling whether damage is hail damage, which is worth reading before any inspection.
Does a bigger hailstone always mean a damaged roof?
No source read for this page says so, and none says the opposite. A NOAA row records a reported stone size at a spot and time. It does not record what happened to any roof. Only an inspection of your own roof, with photos and a written scope, answers that.
Why does the federal spec mention cover board in a hail note?
The note says glass mat and moisture resistant gypsum roof board used as an overlayment can give improved wind, impact and hail resistance. That puts part of the impact answer in the layers under the membrane. Ask any roofer which board, if any, sits under a PVC sheet and who chose it.
Who decides on a PVC roof for a Sterling building?
The owner signs, and for an association or condominium the governing documents may add an approval step. Our Sterling roofing guide sets out the Census building mix and the Loudoun and state paperwork for each building type.
Talk through your roof with Roofers of Arlington
Share the address, what you are seeing on the roof and the decision you need to make. We will tell you what to expect before anything is scheduled.