PVC roofing in Annandale, VA: one table row in the building code

The row that names PVC

The text here comes from an UpCodes page, a third-party copy that labels the code as Virginia's 2021 edition adopting the 2021 International Building Code with amendments. Fairfax County says that since January 18, 2025, all permit applications and plans must meet the 2021 Uniform Statewide Building Code. The table sits under Section 1507.12, which opens by saying single-ply roofing installation shall comply with that section.

Table 1507.12.2, Virginia Construction Code 2021, Chapter 15, as shown on a third-party UpCodes copy opened October 24, 2026.

Two details are PVC-specific. The row pairs PVC with PVC/KEE under one standard, while KEE also has a row of its own. And PVC and TPO are both heat-welded sheets, yet the code gives each a different standard number and no welding words at all. The Annandale roofing guide covers the county permit rows and housing counts that sit around this code.

What ASTM D4434 covers

Read together, the two documents split the job. The standard sets a floor for the sheet as made. The code row only points to that floor. Everything about how the finished roof behaves in fire, wind or heat is left to other parts of the chapter and to tested assemblies, as the next section shows. The version opened is D4434/D4434M-21, listed as active; the ASTM site itself refused an automated request, so the store page and an archived copy (web.archive.org, 2025) were read, and they show the same scope text.

Slope, wind and fire around the row

• Section 1503.1Coverings are installed to the code and to the manufacturer's approved instructions. For PVC this is the main sentence that reaches seams and fasteners, and Section 1507.1 repeats it.
• Section 1507.12.1Single-ply roofs shall have a design slope of not less than 1/4 unit vertical in 12 horizontal, for drainage. The sentence names no material.
• Section 1504.4Adhered or mechanically attached coverings are designed to resist wind pressures set by Section 1609.5.2.
• Section 1504.4.1Fully adhered or mechanically attached single-ply systems shall be tested to FM 4474, UL 580 or UL 1897.
• Sections 1504.5 and 1507.12.3Ballasted single-ply roofs with a slope under 2:12 are designed to ANSI/SPRI RP-4, and stone ballast meets ASTM D448 or D7655.
• Section 1505.1Class A, B and C assemblies are tested to ASTM E108 or UL 790, with a minimum class set by type of construction.

Where Fairfax County fits

The county posts local design load criteria on its codes page, including the wind speed in the tiles below, and says the numbers are the county's own entries. A designer turns those figures into the pressures the chapter calls for. The four tiles are context, not a PVC rule: nothing in the county table mentions a roof membrane. The 4,494 figure is from the 2020 to 2024 American Community Survey and counts homes in buildings of five or more units, the group most likely to meet the commercial permit path below.

1. Permit rowThe county commercial miscellaneous page lists Re-Roof/Re-Line and Roof Repair. It does not name PVC.
2. DocumentsDepending on scope, a Fairfax coversheet and architectural or structural drawings may be needed.
3. ReviewThe page says staff from several offices, including building plan review and the Fire Marshal, may review the package.
4. InspectionAfter the permit is issued, the page says the county must be notified at the stages that need an inspection.

The page calls itself the most common path, not every condition. For houses and townhouses the residential page applies instead, and the county phrases its own exemptions there. This page describes what the county says and gives no advice on a permit: ask Land Development Services how your building and scope are classed. For a general view of the membrane, the PVC roof page and the materials page compare systems, and the commercial roofing page covers low-slope work.

Named and not named

Computed on the chapter text: the word weld appears 0 times and the word reflect 0 times. The thickness and fastener numbers that do appear belong to flashing metal, cap nails, shingles, tile and metal panels, among other products, not to single-ply sheet. That is a statement about this code chapter only. Other documents, such as the Virginia energy code, the maker's data sheet and a designer's specification, may carry those numbers, and none of them was read here.

Thickness

Ask for the sheet thickness as a number in the quote, and for the data sheet it comes from.

Welding

Ask for the installation instructions the quote follows, since the code defers to them.

Wind label

Ask which of the named tests the proposed assembly carries and for which building.

Fire class

Ask for the listing of the whole assembly, not the sheet alone.

Questions that follow from the text

• Does the quote say the sheet meets ASTM D4434, and which maker and product data sheet is it?
• What is the sheet thickness, and what reinforcement does the data sheet describe?
• Which installation instructions govern seams, flashings and edges, and can I have a copy?
• Is the roof adhered, mechanically attached or ballasted, and which named test or design standard applies?
• What is the measured slope, and where does the water leave the roof?
• Which fire-class listing covers the full assembly, including insulation and deck?
• If an old roof stays under the new one, who confirmed the existing building code allows it, and where is that in writing?
• For a condominium or apartment building: has the association or owner approved the system?

Book a phone consultation to talk through an Annandale PVC roof: call (571) 397-6072 or use the consultation page. Have the address, the building type and what you can see on the roof ready. The flat roof page and roof replacement page explain the general work, the services page lists it, and the Annandale guide has the county rows.