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Composite roofing: what the word means, what the code says and what Arlington's papers show
Search for composite roofing and two different products come back under one name: synthetic slate, shake and tile made from polymers, and ordinary asphalt shingles that some documents call composite or composition. This guide separates the two, reads Virginia's residential code chapter on roof coverings, checks the Arlington nominations and county pages for the word, and ends with a written-scope list. It is a neutral reading guide, not an offer of a product.
- 3 different meanings of "composition" or "composite" in the sources read
- 0 roofs called composite in the 31 Arlington nominations searched
- No composite or synthetic shingle named in the code chapter
One word, three meanings
Documents use "composite" and "composition" loosely. These are the three uses found in the sources read for this page.
- Synthetic slate, shake and tile
- NRCA describes synthetic roofing materials as products that simulate traditional coverings such as slate and wood shingles and shakes, and adds that they "do not necessarily have the same properties." NRCA uses the word synthetic, not composite.
- Asphalt shingles
- Fairfax County's historic district guidelines name "composition shingles" in the roof text and label one picture "asphalt/composite shingle." Alexandria's review board policies say original composition roofing may be replaced with architectural grade composition roofing, and treat synthetic slate as a separate item.
- Built-up roofing
- The National Park Service's 1978 roofing brief speaks of a "modern built-up composition roof" for flat roofs that cannot be seen from the street. That is a tar-and-felt system, a different thing again.
The Park Service's slate brief (1992) says artificial mineral fiber slate "is not recommended" for restoration work because it looks man-made. That brief describes a mineral fiber product of its day, not today's polymer shingles, so it is evidence about attitudes in preservation, not about any current product.
Synthetic products "do not necessarily have the same properties" as the coverings they simulate.
NRCA, Roofing Materials
For the asphalt meaning, see our guide to fiberglass and asphalt shingles. The rest of this page is about the first meaning, the polymer-based look-alikes, while pointing out where a rule applies to both.
What Virginia's code chapter says
Roof coverings for houses and townhouses fall under chapter 9 of the 2021 Virginia Residential Code. The text below comes from the UpCodes copy, a third-party site that marks Virginia as "Adopts With Amendments." The official text is the one the county applies, so use this as a map and confirm with the county.
What the chapter names
Asphalt shingles, clay and concrete tile, metal roof shingles, mineral-surfaced roll roofing, "slate and slate-type shingles," wood shakes and shingles, built-up, metal panels, modified bitumen, single-ply, foam, liquid-applied and photovoltaic shingles. No entry is called composite, synthetic or polymer.
R904.1 and R905.1
Roof assemblies and roof coverings are applied under the chapter and the manufacturer's installation instructions. This line is how a product without its own section is still governed.
R904.2 and R904.3
Materials must be compatible with each other and with the building, and must conform to the applicable standards listed in the chapter.
R904.4
Packages carry the manufacturer's identifying marks and approved testing agency labels where required, so the label on the bundle is part of the paper trail.
R902.1
Class A, B or C roofing applies where the jurisdiction requires it or where the roof edge is under 3 feet from a lot line, and listed roofing is tested to ASTM E108 or UL 790.
Where a polymer shingle sits in that picture
The slate section, R905.6, requires solid sheathing, a slope of at least 4 in 12, ASTM C406 slate and two fasteners per slate. It speaks of slate shingles, and the chapter overview adds "slate-type" to its list. The sections read here do not say how a polymer product qualifies as slate-type or under which standard. That question belongs to the building official and the product's own test paperwork. Ask the county which documents it wants on file for a covering the chapter does not name.
Fire and wind labels: what each test covers
A label is shorthand for a test. The test's own scope page says what it was built to measure, and the scope matters when the product is not an asphalt shingle.
| Label or standard | What its scope says | Question it raises |
|---|---|---|
| ASTM E108 and UL 790 (fire class A, B, C) | Relative fire characteristics of roof coverings exposed to simulated fire sources outside the building, applied "as intended for use." Class A covers severe exposure, B moderate, C light. | Was the product tested over the same deck and underlayment your roof will have? |
| ASTM D7158 (wind class D, G, H) | Calculates wind resistance of asphalt shingles. Designs that depend on interlocking or product rigidity cannot be evaluated by it. | If the product is not an asphalt shingle, which wind test does its label name? |
| ASTM D3161 (fan-induced wind) | Covers many discontinuous, air-permeable steep-slope products whose wind resistance comes from rigidity or interlocking. It does not measure structural performance or uplift resistance. | At what slope was it tested, and does your slope match? |
| UL 2218 (impact) | A laboratory test that drops steel balls onto the covering. ARMA says it is of interest to owners, which is different from a code requirement. | Is an impact class claimed, and where is the test report? |
ASTM scope text from archived copies of astm.org pages (January and February 2025). ARMA is an asphalt roofing trade group, so its page describes asphalt shingles.
ARMA's page also mentions an ICC Evaluation Service document, AC438, "Acceptance Criteria for Alternative Asphalt Roofing Shingles," as another way to show compliance with ICC codes. It is written for asphalt shingles. Other products have their own paperwork, and the code's phrase "approved testing agency labels" is the hook for asking to see it.
Fastening: where the answer sits
Neutral sources give one firm rule for fastening a covering that is not named in a table: follow the manufacturer's installation instructions. The ASTM wind scopes say products are applied to the test panel in accordance with those instructions. The code says the same in R904.1 and R905.1.
- The fastener count and placement come from the installation sheet for the exact product and slope, not from a general rule about shakes or slate.
- The only fastener count printed in the chapter for a slate-like covering is two per slate, and that sits in the section for real slate.
- The D3161 scope says the test applies at a slope of 2 in 12 or the lowest slope the instructions permit, so the installation sheet's minimum slope belongs in the scope too.
If the installation sheet and a roofer's habit differ, the code line points to the sheet. Ask for the printed instructions to be attached to the written scope.
What the Arlington papers say
The materials page tallies the roof materials named in 24 Arlington historic nominations and finds no composite shingle. For this page the search was widened to every nomination text on file, 31 in all, plus the county pages used on the Arlington hub.
- 31 nomination texts searched, covering every form on file.
- 2 files contain the word composite, and neither describes a roof covering.
- 0 hits for composite, synthetic or polymer on the six county pages read.
The two hits are a "composite window" in the Lyon Park nomination and, in the Lee Gardens North nomination, flat-roofed buildings whose metal coping hides "built-up composite cladding," while the gable roofs are asphalt shingle. Neither is a polymer shingle. Synthetic, polymer, imitation and artificial found no roof either. The scans carry text-recognition errors, so a missed word is possible, and an owner should ask about a specific building.
The neighbors do name the material. Alexandria's roofing guidance lists imitation slate among later 20th-century materials and allows synthetic roofing on later buildings if it suits the style and period. That is Alexandria's document, not Arlington's. Arlington's pages read here are silent on composite and synthetic coverings, which means the answer for a given roof comes from the county's staff.
Historic review and substitute materials
Outside a local historic district, the question is the permit path on the hub. Inside one, a substitute covering is a historic-review question first.
What the county asks
A Certificate of Appropriateness is required for exterior alterations, with an exception for routine maintenance, repairs and replacements using the same materials. A change of material is not a same-material replacement.
What the federal standard asks
Standard 6 asks a replacement feature to match the old in design, color, texture and other visual qualities and, "where possible, materials." NPS says these are the standards local commissions most often apply.
The 1978 Park Service brief adds that a readily visible roof calls for a substitute matching scale, texture and coloration as closely as possible. Our slate roofs guide reads the Arlington documents on slate, including the Buckingham design guidelines, and is the place to start if the roof being replaced is slate. For a condominium or co-op, the condo and co-op guide covers who approves a change of covering.
A written scope for a composite roof
Whatever the product, a scope that names these items can be checked line by line against the manufacturer's sheet and the county's answer.
- Which meaning of "composite" applies: polymer-based synthetic slate, shake or tile, or asphalt shingle.
- The product's manufacturer, line, color and the label wording on its package, per R904.4.
- The fire class and the test it came from, E108 or UL 790, and the deck and underlayment it was tested over.
- The wind label, which test it names and the slope and exposure it covers.
- Fastener type, count and placement, quoted from the installation instructions, which are attached.
- Underlayment, ice barrier, flashing, starter, hip and ridge parts, each by name.
- Decking: whether any is replaced, how much, and the effect on the county permit threshold.
- Whether the address is in a local historic district, and who is asking the county for approval.
- Removal of the old covering down to the deck, as R908.3 describes for roof replacement.
For the general shape of a replacement, see roof replacement. To talk through your building, book a phone consultation. We would ask for the address, the building type, what the roof looks like now and what you have been quoted. Nothing on this page is engineering or legal advice.
Where each fact on this page comes from
All pages below were opened on October 25, 2026. ASTM pages came from archived copies of astm.org. Arlington County pages are blocked to automated downloads, so county text comes from archived copies.
- NRCA: Roofing Materials
- Virginia Residential Code 2021, chapter 9, UpCodes copy (third party)
- ASTM E108 scope, ASTM D7158 scope and ASTM D3161 scope (archived copies)
- ARMA: Asphalt Shingle Product and Test Standards
- NPS Preservation Brief 4: Roofing for Historic Buildings (1978)
- NPS Preservation Brief 29: Historic Slate Roofs (1992)
- Secretary of the Interior's Standards for Rehabilitation
- Fairfax County HOD Design Guidelines (final draft, January 2026)
- Alexandria BAR administrative approval policies (amended September 24, 2025) and roofing chapter, Old and Historic Alexandria District (July 2025)
- Virginia Department of Historic Resources: Arlington nomination PDFs
- Arlington County: Certificate of Appropriateness (archived December 6, 2025)
Questions people ask
Is composite roofing the same as architectural shingles?
Not always, and the sources split on this. Fairfax County's historic district guidelines label one roofing type "asphalt/composite shingle", and Alexandria's review board uses "architectural grade composition shingles" for a grade of asphalt shingle. NRCA, the roofing contractors association, uses "synthetic" for products that simulate slate and wood. Ask which product is meant before you compare anything.
Does the Virginia residential code have a section for synthetic or composite shingles?
The chapter 9 overview in the UpCodes copy of the 2021 Virginia Residential Code lists the coverings it addresses, and none is called composite, synthetic or polymer. It does list "slate and slate-type shingles". The chapter still sets general rules that reach every covering: manufacturer's installation instructions, compatible materials and labeled packaging.
What do the fire class and wind class labels on a package mean?
The fire class (A, B or C) comes from ASTM E108 or UL 790 tests of a roof covering against fire from outside the building. Wind labels come from different tests, ASTM D3161 and D7158, and the D7158 scope says it covers asphalt shingles. A label only describes the test it names, so read the label together with the manufacturer's sheet for your product.
Do any Arlington historic nominations mention composite roofing?
No roof in the 31 nomination texts we searched is described as composite, synthetic or polymer. The word composite appears twice: once for a window in the Lyon Park nomination and once for built-up cladding behind metal coping on flat-roofed buildings in the Lee Gardens North nomination. The scans carry some text-recognition errors, so ask Historic Preservation about a specific building.
Can a synthetic roof replace slate in an Arlington historic district?
A local district needs a Certificate of Appropriateness for exterior alterations, except routine maintenance, repairs and replacements using the same materials. The Secretary of the Interior's Standards ask a replacement to match the old in design, color and texture and, where possible, materials. Whether a substitute is accepted for your building is a question for the county's historic preservation staff, not a roofer.
Does a composite roof need an Arlington building permit?
The county's residential table sorts re-roofs by how much decking is replaced, not by covering type. The table on the Arlington hub page shows the rows, and the Permit Arlington Center, 703-228-3800, answers cases the table does not list.
What should a written scope for a composite roof name?
The product by its manufacturer's full name and line, the standards and labels it carries, the fastener type and count the installation sheet requires, the underlayment and flashing it calls for, and who gets the documents. The scope list below turns that into checkable lines.
Does Roofers of Arlington install composite roofing?
This page is a neutral guide to the material and the paperwork. The company installs, repairs and replaces roofs, including flat and metal systems. To talk through your building and what to ask for in writing, book a phone consultation or call (571) 397-6072.
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.