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EPDM roofing in Annandale, VA: the exposure record, from storm rows to sunlight
An EPDM roof is a dark rubber sheet that sits in full sun and takes whatever the sky sends. This page lines up the weather record that names Annandale, counted a new way, with the neutral sources on how a black membrane meets heat, ultraviolet light, ozone and wind. It does not rate any roof. It shows what the sources say and what to ask.
- 9 different NOAA place labels cover the 28 Annandale entries
- 9 of 13 Annandale wind entries fall in July or August
- Black reflectance 0.05 against white 0.80 in the federal spec
Twenty-eight entries, nine labels
NOAA's Storm Events database logs weather by county zone, and the National Weather Service picks a place label for each entry. For Fairfax County the 2016 to 2026 files hold 927 rows. Twenty-eight of them mention Annandale in a label or in the narrative. Counted by the label the forecaster chose, they spread over nine names, and only two carry the name Annandale itself.
| Place label in the file | Entries | Event types |
|---|---|---|
| Tremont | 8 | Flood and flash flood |
| Lake Barcroft | 7 | Wind 5, flood 2 |
| Merrifield | 4 | Flood, flash flood, wind |
| Annandale | 2 | Wind 2 |
| Ilda | 2 | Wind 2 |
| Ravensworth | 2 | Flood 2 |
| Masonville, Springfield, Enola | 1 each | Wind 3 |
NOAA National Centers for Environmental Information, Storm Events detail files for 2016 to 2026, Fairfax County rows; counts computed for this page, opened October 20, 2026.
The point of the cut: a label is where the forecaster placed the report, not a boundary. An Annandale owner reading the table should treat it as a spread of reports around the Little River Turnpike and Accotink Creek area, not as a count of events on one roof. The Annandale roofing guide counts the same entries by event type and covers the permit rows.
When the entries fall
- 2016 to 2024The entries run across these years. None is dated 2025 or 2026 in the files opened, and a gap in a reported-events log is not proof of calm weather.
- July and AugustOf the 13 wind entries, 9 fall in July (6) or August (3). The other four are February, April, May and October.
- 1:53 pm to 6:48 pmThose nine summer wind entries begin in this window on the file's clock. Afternoon is also when a sun-warmed roof is hottest, a link the sources below leave to the designer.
The wind speeds are estimated gusts: 50 knots six times, 52 knots four times, then 55, 60 and 61 knots once each. Every one of the 13 narratives names fallen trees. One, from April 6, 2017, with the label Annandale, says a large tree fell onto a house. None uses the word roof for a covering that was torn or lifted.
Black membrane in a Virginia July
No Annandale weather station was opened for this page. NOAA's 1991 to 2020 climate normals exist for two nearby airports, and they bracket the area.
The same Storm Events files hold 24 Fairfax County heat entries, 16 typed Heat and 8 Excessive Heat. All 24 fall in July (15) or August (9), and their narratives cite heat indices of about 105 to 110. None names Annandale, so they are county-zone rows, not local ones.
Full sunshine "can increase heat index values by up to 15" degrees Fahrenheit.
National Weather Service, Heat Forecast Tools pageHeat index values describe air in shade. They are not a roof surface reading, and the sources opened for this page give no surface temperature for an Annandale roof. What the federal sources do give is a scale for how much sunlight a surface rejects.
The federal guide specification for EPDM roofing (UFGS 07 53 23, August 2025) defines the Solar Reflectance Index so that a standard black, with reflectance 0.05, scores 0 and a standard white, 0.80, scores 100. The EPDM Roofing Association says the membrane is sold in black, gray and white, with varying reflectivity.
The EPA describes a cool roof as one with high solar reflectance and high thermal emittance, and lists single-ply membranes with light or cool pigments as one low-slope product type. A standard black EPDM sheet is not that product.
The association's own cool-roofs page argues for weighing reflectivity together with insulation, climate and the whole system, not any single trait. Neither source puts a number on what a black sheet adds to a given Annandale building, so that question goes to the designer.
Ultraviolet light and ozone
What the trade group says
The EPDM Roofing Association lists high resistance to ozone and weathering, and to ultraviolet radiation, as attributes. In its freezer answer it also says heat-aging tests show "no changes to physical properties". These are statements from membrane makers.
What the federal spec asks for
It requires the principal polymer to be more than 95 percent EPDM and the sheet to meet ASTM D4637, Type III for the fleece-backed option. It calls for an ultraviolet resistant polypropylene mat under ballast.
What it does not say
Neither source gives a dated field result for Annandale or for Fairfax County, and this page does not either. Wear from sun is a reason to ask for the product data sheet, not a number.
What the spec lists as defects
Its defect list names splits, cracks, seams that separate, shrinking that bridges or tents the membrane, and excessive weathering due to defective materials or installation workmanship.
The association also says that EPDM is designed for non-residential roof systems. Of Annandale's 14,474 homes, 6,802 are detached houses and 4,494 sit in buildings of five or more units, so the owner type decides how that line applies. Our EPDM roof guide and the materials page cover the membrane itself.
Wind: from gust to uplift label
A gust of 50 to 61 knots is a weather record. A roof needs a design number. The federal guide specification shows how a wind number becomes a label on a roof system.
- Calculate the load. The wind uplift requirement is set by ASCE 7-22 loading or by the building code that applies.
- Pick a rated system. An FM rating of 1-90 correlates to a maximum uplift calculation of 45 pounds per square foot, and the rating includes a safety factor of 2.
- Choose the attachment. Standard methods in the spec are loose-laid ballasted and fully adhered. It prohibits mechanical fastening in the field of an EPDM roof, and allows a combined adhered and perimeter-fastened method for extreme wind.
- Check the edges. The spec asks for the perimeter and corner attachment layout to be shown. It does not specify stone ballast where wind zones exceed 100 miles per hour.
Virginia's building code uses a wind number too. Its permit exemption for unlimited roof covering replacement in groups R-3, R-4 and R-5 applies only where the nominal design wind speed is not over 100 miles per hour. The same item exempts 100 square feet or less in all groups. Which wind speed applies to an Annandale parcel is for Fairfax County to say.
The association says EPDM systems can be designed to meet FM 1-60, 1-90 and 1-120 ratings and greater. That is a ceiling for the assembly, not a statement about any roof now standing. The roof replacement page explains how a scope names attachment and edge details.
Flood rows and ponding
What the rows say
Fifteen of the 28 Annandale entries are flood (12) or flash flood (3). They are spread over ten months, from February to December, and they mostly describe Accotink Creek gauges and flooded roads; one reports water in homes. They say nothing about water standing on a roof.
What the association says
On a flat roof, drains belong in low areas, and crickets, saddles or tapered insulation can steer water. It says ponding raises the cost of repairs and the moisture risk after a puncture.
Rain on a roof and rain in a creek are different problems. A flood row tells you about the ground. A ponding question is about slope, drains and the deck, and it needs a roofer or engineer on the roof. The flat roof page lists what that visit looks at.
What to ask before a quote
- Which color and thickness class is the membrane, and which data sheet and installation instructions does the quote follow?
- Is it fully adhered, ballasted or fastened at the edges, and what wind label does that assembly carry?
- Who calculated the wind load, and for which building and design wind speed?
- Where do the drains sit, and does the scope include crickets or tapered insulation for any low spot?
- If the building has rooftop equipment, how is reflected light or heat from the roof handled?
- Which Fairfax County permit row applies to this building, and who pulls it?
Book a phone consultation to talk through an Annandale EPDM roof on (571) 397-6072. The services and commercial roofing pages show what the site covers, and the roofing insurance explainer covers storm claims.
Documents behind each line
- NOAA Storm Events detail files, Fairfax County rows, counted for this page; opened October 20, 2026.
- NOAA NCEI 1991 to 2020 monthly normals, Washington Dulles and Reagan National stations; opened October 20, 2026.
- National Weather Service, Heat Forecast Tools; opened October 20, 2026.
- UFGS 07 53 23, EPDM Roofing (August 2025), a federal guide specification and not a county rule; opened October 20, 2026.
- EPDM Roofing Association, Why EPDM, FAQs and Cool Roofs pages, a trade group of membrane makers; opened October 20, 2026.
- EPA, Using Cool Roofs to Reduce Heat Islands; opened October 20, 2026.
- 13VAC5-63-80, Virginia Administrative Code; opened October 20, 2026.
- Fairfax County Land Development Services, Does My Project Require a Permit?; opened October 20, 2026.
- Census Bureau ACS 2024 five-year table B25024, Annandale; opened October 19, 2026.
Questions people ask
Why is an EPDM roof black, and does that matter in Annandale summers?
The EPDM Roofing Association says the membrane comes in black, gray and white. The federal guide specification defines its reflectance scale so that a standard black scores 0.05 and a standard white 0.80. Black absorbs more sunlight. What that means for one building depends on insulation, ventilation and use, so ask the designer.
Does the NOAA record say any Annandale roof was damaged?
Not in the rows counted here. Of the 28 Fairfax County entries that name Annandale, 13 are thunderstorm wind and all 13 narratives mention trees. None of the 28 uses the word roof. The database logs reported events only, so it cannot prove that no roof was hurt.
What is the difference between heat index and roof temperature?
The National Weather Service heat index measures how hot the air feels to a person in shade. Its page says full sunshine can raise heat index values by up to 15 degrees Fahrenheit. It is not a measurement of a roof surface, and no neutral source opened for this page gives a roof surface temperature for Annandale.
Does EPDM resist ultraviolet light and ozone?
The EPDM Roofing Association lists high resistance to ozone and weathering, and to ultraviolet radiation, among the membrane attributes. It is a trade group of membrane makers, so treat that as the industry view, and ask which product data sheet your quote relies on.
Is EPDM meant for houses?
The association says EPDM is a commercial product designed for non-residential roof systems. In Annandale 47.0 percent of homes are detached houses, so a house owner should ask a roofer why a given membrane suits that roof and who stands behind the detail work.
What is a wind uplift rating?
It is a label from a testing body. In the federal guide specification, a rating of 1-90 from FM correlates to an uplift calculation of 45 pounds per square foot, with a safety factor of 2 built in. Required values come from the wind loading rules for the building, so ask the designer or the county.
Does Fairfax County require a permit for an EPDM re-roof?
The county permit page lists roof shingle replacement among work that needs no permit and roof repairs among work that does, and says its list is not exhaustive. It has no row that names EPDM. The state code carries its own exemptions, so ask Land Development Services how your scope is classed.
Why do flat roofs need drains in the low spots?
The EPDM Roofing Association says drains should sit in low areas to avoid ponded areas, and that crickets, saddles or tapered insulation can move water. It also says ponding adds repair expense and moisture risk if the membrane is punctured. Annandale has 15 flood or flash flood entries, and none mentions a roof.
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.