EPDM roofing in Fairfax, VA: what the local documents say, and what the sheet standard offers

One sentence in three City chapters

The City of Fairfax Design Guidelines divide the City into overlay districts, and each district has a New Construction chapter with a roof section. All three chapters carry the same permission for rubber membrane roofs. The text below sets out where each sits, because the district decides whether a design review applies at all.

Read carefully, the sentence is permissive and conditional. It allows the material where the roof cannot be seen from public areas, and it says nothing about a visible roof. For visible roofs in the ACOD chapter, a different guideline names standing-seam metal, architectural shingles, slate and artificial slate. The guidelines never call the rubber membrane EPDM, so the reader has to match the term to the sheet.

These are New Construction chapters. Whether a re-cover of an existing building is read against them is not stated, and that is a question for City staff. The Fairfax hub page compares the City and county permit routes for the same building.

Where the documents go quiet

A silent document is a finding. Here is what each source says about EPDM, in the order a reader would meet them, from the guideline text down to the code.

• Guidelines, rehabilitation chapterThe Historic Overlay roof guidelines for existing buildings steer owners toward slate and standing-seam metal and warn against switching a historic roof to non-historic materials. No rubber membrane appears in that roof list.
• Guidelines, word countIn the extract read, EPDM, TPO and single-ply each appear 0 times. The phrase rubber membrane appears 7 times: six in the roof-material passages above and one describing a gutter lining.
• City review triggerThe City flowchart says architectural review is required for improvements visible from the public realm. Roof visibility therefore decides review, and the guideline sentence uses the same test.
• County permit pagesFour Fairfax County Land Development Services pages were searched on October 20, 2026. None contains the words EPDM, membrane, rubber or single-ply. They list Re-Roof/Re-Line and Roof Repair as permit types.
• State and codeThe Virginia exemption rule and the 2021 codes name roof coverings by standard, not by guideline wording. The next section picks up the standard.

Reinforced, non-reinforced and fleece-backed

The ASTM page read here is an archived copy of the 2015 edition, and it lists later reapprovals, so check the current edition at ASTM before relying on any clause. The sources opened do not print what Type I and Type II mean. The federal specification below does tie Type III to fabric or fleece backed membrane, so the type labels point to construction, not to quality grade.

Virginia names the same standard. The 2021 Virginia Construction Code table of single-ply standards pairs EPDM with D4637. The 2021 Virginia Residential Code says thermoset single-ply roof coverings shall comply with D4637 or D5019 and be installed to the chapter and the manufacturer instructions. Both set a design slope of at least one quarter unit in 12. The code text was read in third-party UpCodes copies, because the code publisher blocks automated access.

Thickness figures from a federal specification

Unified Facilities Guide Specification 07 53 23 covers EPDM roofing for federal buildings. The August 2025 edition is public, and it cites D4637 and shows how thickness and reinforcement are written when an owner has an engineer behind the order. It is a guide for federal designers, not a Virginia rule, and a private owner can use it as a list of questions.

UFGS 07 53 23, EPDM Roofing, August 2025, paragraph 2.2.1 and its designer notes, opened October 20, 2026. A mil is one thousandth of an inch.

Backing is not counted

The specification says the thickness it names is exclusive of the backing, so a figure with fleece included is a different number from the rubber sheet alone.

A tolerance is written in

Delivered membrane may be no more than 10 percent under the specified thickness. A quote that gives one number has not said how it was measured.

Polymer content

The specification asks that the principal polymer be greater than 95 percent EPDM, a materials question to put to the manufacturer.

Reinforced where winds are higher

A designer note says to use reinforced membrane in wind zones over 100 mph, within 5 miles of coastline or within 1,500 feet of open water, and it bars stone ballast in the same zones.

Cut edges of reinforced sheet

The installation text calls for lap sealant on adhesive seams and on all cut edges of reinforced membrane.

The specification also states a preference: fully adhered membrane over at least two layers of rigid board insulation. With Type III it names spray-applied compound, spray foam adhesive or hot asphalt as the adhesive. Those are choices for a federal project, not a local permit rule. The sources opened here print no 45 mil class, so this page describes none.

Reading an EPDM quote

1. Ask which construction. Non-reinforced, scrim-reinforced or fleece-backed are different sheets under one standard. The quote should name the one chosen.
2. Ask what the number measures. A thickness in inches or mil should say whether backing is included and whether it is nominal.
3. Ask for the standard. The product data sheet should list ASTM D4637 or the other standard the code names.
4. Ask how it attaches. Fully adhered, ballasted and mechanically attached roofs behave differently in wind, and D4637 does not choose among them.
5. Ask about the edges. Flashing, seams and cut edges are where the guide specification puts its sealant and detail instructions.

• For a building inside the City, has staff said whether the roof is visible from public areas and whether review applies?
• For a parcel in the county, has the plans reviewer confirmed the permit type, Re-Roof/Re-Line, and the wind clause for the parcel?
• In a historic district, has staff said whether an application is required, as the state exemption rule allows?

Roofers of Arlington installs, repairs and replaces roofs, including flat roof systems. The general EPDM page and the materials overview compare membranes, the commercial roofing page covers larger buildings, and the roof replacement page explains scope and quote structure. To talk through a Fairfax EPDM roof, book a phone consultation, or go back to the Fairfax hub for the City and county comparison.