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TPO roofing in Burke, VA: how a Class A, B or C fire label is read on a membrane roof
A roofing quote may say Class A. In the Virginia code that is a result for a tested assembly, not a property of a membrane name. This page reads the commercial chapter, the residential chapter and the Fairfax County permit wording side by side, and says plainly where each one is silent about TPO.
- 3 classes: A severe, B moderate, C light exposure
- TPO is not named in the code's Class A list
- Insulation and membrane are tested as one assembly
Why a class label is not a product name
Virginia's commercial roof chapter sorts roof assemblies into three fire classes. Each is defined by how the assembly did against a fire test exposure, and each must be listed and identified by an approved testing agency. The section on the three classes uses the words severe, moderate and light.
"effective against severe fire test exposure"
Virginia code chapter 15, section 1505.2 on Class A, UpCodes copy read October 20, 2026Classes are tested under ASTM E108 or UL 790. The Burke roofing guide covers the area more broadly. This page stays with the fire label and a membrane roof, the part of a TPO quote that is easiest to misread.
Class A
Severe fire test exposure.
Class B
Moderate exposure.
Class C
Light exposure.
Nonclassified
Approved material not listed as A, B or C.
Two code paths, one roof
Commercial chapter 15
Section 1505.1 sets a minimum covering class by construction type in a table. A footnote allows nonclassified coverings on Group R-3 and Group U buildings where the fire-separation distance is at least 6 feet from the leading edge of the roof. The single-ply section, 1507.12, lists TPO under ASTM D6878 and sets the slope floor.
Residential Code chapter 9
Section R902.1 requires Class A, B or C roofing where a jurisdiction designates it by law or where the roof edge is less than 3 feet from a lot line. The thermoplastic single-ply section, R905.13, names ASTM D4434, D6754 or D6878 and says to install per the chapter and the manufacturer's instructions.
UpCodes copies of the 2021 Virginia codes, a third-party site. The official text controls.
The two paths differ in what triggers a label. The commercial table works from construction type. The residential rule works from a lot-line distance or a legal designation. A Burke building owner has to learn which path the building falls under before reading any quote. In Burke CDP about a third of homes are attached, so both detached-house and attached-home questions come up.
- Burke CDP: 4,647 of 13,878 homes are attached, 33.5 percent (ACS 2024 5-year).
- Burke Centre CDP: 2,884 of 6,247 homes are attached, 46.2 percent.
- The Census counts homes, not roof materials. It does not say which roofs are membranes.
The label belongs to the assembly
The word in the code is assembly. A class is earned by a stack of layers tested together, and the code's own language follows that logic. Section 1508.1 allows above-deck insulation if it is covered with an approved roof covering and passes NFPA 276 or UL 1256 when tested as an assembly. In plain terms, the insulation and membrane are judged as a pair.
- The deck: wood panels, steel or concrete. The Class A list in 1505.2 names several coverings over noncombustible decks.
- The insulation board and how it is attached.
- Any cover board or separation layer.
- The membrane, and whether it is attached mechanically or adhered.
- Edge metal and flashings, which the quote has to name as well.
The list of coverings that count as Class A without a separate test names brick, masonry, concrete deck, metal, clay or concrete tile and slate, with conditions. A single-ply membrane is not named in it. For a TPO roof the class therefore rests on a listing for the full build-up, not on the membrane name. If the quote swaps the insulation or the deck, the listing may no longer match.
A data sheet may print a class for a membrane tested over a specific deck and insulation. That is a statement about that build-up. Ask for the listing that names your deck, insulation and attachment method.
Where the pages say nothing about TPO
| Page | What it says | Where it is silent |
|---|---|---|
| Fairfax County, when a permit is required | Residential no-permit list names replacement of roof shingles; commercial list names replacement of less than 100 square feet of roof covering; roof repairs appear on permit lists | No membrane named; the list is described as not exhaustive |
| 13VAC5-63-80, item 14.5 | Unlimited roof covering replacement exempt in R-3, R-4 and R-5 unless the nominal design wind speed is above 100 mph; 100 square feet or less in all groups | Does not name a material or a fire class |
| Item 14.6 | 256 square feet or less of decking exempt in R-3, R-4, R-5 unless it was required to be fire-retardant-treated or to form a fire-rated wall termination | Does not say which townhome roofs have such decking |
| Chapter 15, section 1512.1 | Reroofing and repair follow Chapter 15 and named sections of the Virginia Existing Building Code | The VEBC sections were not opened for this page |
The fire-rated decking exception is the one with a fire link. The county's permit page repeats it for townhomes. It tells an owner that a small deck repair on an attached home can have a fire reason behind it, and it does not tell the owner which decks. Ask the building office before assuming that a repair is exempt.
None of the pages read says that TPO is, or is not, a Class A, B or C covering. The code leaves that to the listing of the assembly.
Reading a label on a quote
- Which class does the quote name, and which listing does it cite for that class?
- Does the listing name my deck, my insulation and my attachment method?
- Is the above-deck insulation covered by the NFPA 276 or UL 1256 assembly test named in section 1508.1?
- Is the roof edge less than 3 feet from a lot line, or is the building in a designated area under the residential rule?
- If the building is a townhome, was the deck required to be fire-retardant-treated or to form a fire-rated wall termination?
- Does the quote name the design slope, with the code floor of one quarter unit vertical in 12 for membrane roofs?
- If an association governs the building, has it approved the system and color in writing?
The TPO roofing page covers the membrane itself, and roofing materials compares the other systems. A flat or low-slope building may also fit flat roof or commercial roofing, and roof replacement explains a full scope. Roofers of Arlington installs, repairs and replaces roofs, and the services page lists what is covered. Book a phone consultation to talk through a Burke TPO roof: we would ask your address, whether the building is a house, townhome or larger building, and what you can see from the ground. See also the Burke guide and service areas.
Pages read for this guide
Each page below was opened on October 20, 2026. The ASTM and UL standards themselves could not be opened, so nothing here describes how the fire tests are run.
- Virginia Building Code 2021, chapter 15, as shown on UpCodes (third-party copy)
- Virginia Residential Code 2021, chapter 9, as shown on UpCodes (third-party copy)
- Virginia Administrative Code, 13VAC5-63-80, exemptions from permits
- Fairfax County Land Development Services: Does my project require a permit
- Census ACS 2024 5-year, table B25024, Burke CDP
Questions people ask
Is a TPO roof automatically Class A?
No source read for this page says so. The code lists coverings that count as Class A, such as masonry, metal, tile and slate, and a single-ply membrane is not among them. A class applies when the exact assembly is listed and identified by an approved testing agency.
Which test standards does the Virginia code name for roof fire class?
Both the commercial chapter and the Residential Code say that roofing required to be listed shall be tested under ASTM E108 or UL 790. This page could not open either standard, so it does not describe how the tests are run.
Does a house in Burke need a Class A, B or C roof?
The Residential Code requires one in jurisdictions designated by law, or where the roof edge is less than 3 feet from a lot line. Whether your roof edge meets that test is a measurement from your own survey. Ask the Fairfax County building office.
Does insulation under a TPO membrane change the fire label?
The commercial chapter lets above-deck insulation be used if it is covered by an approved roof covering and passes NFPA 276 or UL 1256 as an assembly. So the insulation and the membrane are judged together, and a swap of either should be checked against the listing.
Why does the Fairfax permit page mention fire rated roof plywood on townhomes?
The county's no-permit list excludes small plywood replacements where the plywood is required to be fire rated, such as townhomes. The state exemption says the same thing for decking required to form a fire-rated wall termination. Ask whether your townhome roof deck falls under it.
Does a flat TPO roof have a minimum slope in the code?
Both codes set a design slope of not less than one quarter unit vertical in 12 for single-ply membrane roofs, which is a 2 percent slope. The slope sentence concerns drainage and is separate from the fire class.
Where do I check the actual code text?
The page copies used here are from UpCodes, a third-party site, and may differ from the state's own publication. Check the Virginia Department of Housing and Community Development text or ask the Fairfax County building office before you rely on a section number.
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.