TPO Roofs in Chantilly, VA: Reflective Roofs in County Policy
A white flat roof invites two guesses: that the county asked for it, and that it must be TPO. Fairfax County's own text answers the first with a short, optional line and says nothing on the second. Here are the documents in the order they were written.
The paper trail
Which county documents shape a Chantilly office roof, and when were they written?
The countywide Policy Plan and the Dulles Suburban Center area plan for Route 28 and Westfields.
- 1991
The area plan says it was adopted this year as the base of a 20-year plan for land newly named the Dulles Suburban Center.
- 2015
The same plan reports that about 75 percent of the roughly 6,600 acres was zoned for commercial or industrial use as of this date.
- December 9, 2025
The Policy Plan's Environment element carries this amendment date. It holds the green building policies below.
- July 14, 2026
The Dulles Suburban Center text carries this amendment date. It describes mid-rise offices along Route 28 and a larger concentration at the Westfields Business Park.
- October 14, 2026
We read both pages for this guide. Recheck before relying on it.
A reflective roof is one example in a list
Policy a offers “vegetated and/or highly reflective roofs and shade structures to increase resilience and reduce impacts of heat island” among practices that are “not limited to” the list. It names no material and sets no reflectance figure.
What stays unsaid
Does the Westfields part of the area plan add a roof rule on top?
We read the Land Unit J text, the unit that is almost all Westfields, and searched it for LEED, green building, reflective and roof. None appears. Across the whole area plan, the phrases cool roof and heat island appear nowhere.
Policy c says it applies “unless otherwise recommended in the applicable Area Plan.” Our reading: with no recommendation to the contrary in the Westfields text, the countywide wording is the nearest guidance. Whether it reaches a roof job is for county planning staff.
Nothing in either text says a roof replacement is a “major renovation,” and neither names TPO, PVC or EPDM. The Chantilly EPDM page reads that plan's screening sentence.
Objective 13
Where does a reflective roof appear in the Policy Plan, and how firm is the wording?
Four lines of the green building policies, set out left to right in the order the text gives them.
- Policy a: encourage
Green building practices in new development and renovation, drawn from a list that “may include, but are not limited to” more than a dozen items. One item is vegetated and/or highly reflective roofs and shade structures.
- Policy b: encourage
Commitments to certification under a recognised rating system, such as LEED or an equivalent program that is independent and third-party verified.
- Policy c: ensure
In Suburban Centers, unless the area plan says otherwise, zoning proposals for nonresidential development should reach LEED Silver or an equivalent.
- Policy i: ensure
Zoning proposals for adaptive reuse, major renovation or building retrofit should include green building practices sufficient for certification.
The roof line sits in the softest column. The firmer lines ask for a certification outcome and leave the route to the applicant.
The TPO question
What can a white membrane prove about itself?
Colour is not a name
- What you see
- A white sheet from the street or a window.
- What it can mean
- The Single Ply Roofing Industry association says sheet membranes come in black, white and many other colours, so white may be TPO, PVC or EPDM.
- Who to ask
- The owner, for the membrane name in writing.
Cool has no single definition
- What you see
- A listing that calls a roof cool or reflective.
- What it can mean
- The EPA calls solar reflectance the most important cool roof trait and adds thermal emittance. The Cool Roof Rating Council says it sets no definition of cool and leaves that to the code or program asking.
- Who to ask
- The office or program that cites the rating.
The paper name is a standard
- What you see
- A data sheet or a proposal that says TPO.
- What it can mean
- The 2021 model building code lists TPO under ASTM D6878. A trade abstract describes thermoplastics such as TPO as sheets fused together by heat welding.
- Who to ask
- The roofer who last worked on it.
Seams, thickness and reroofing limits live in the Northern Virginia TPO guide and the flat roof guide.
FAQ
Questions about reflective roofs, county policy and a Chantilly TPO roof
Does Fairfax County require a white or reflective roof in Chantilly?
Not in the text we read. The Policy Plan lists highly reflective roofs as one practice that “may” be used under a policy that encourages green building, and the Westfields part of the area plan does not mention it. Ask planning staff about your project.
What is the difference between the Policy Plan and the Dulles Suburban Center plan?
The Policy Plan applies countywide. The area plan covers one part of Chantilly and the land around Route 28. The Policy Plan's LEED Silver line defers to the area plan when that plan recommends something different.
Does a white roof mean the membrane is TPO?
No. White sheets are also made in PVC and EPDM. The reliable handle is the product data sheet, where TPO is tied to ASTM D6878.
Is a CRRC rating the same as being a cool roof?
The Cool Roof Rating Council says it does not define cool. A listing tells you the product was rated, and the code or program you are dealing with decides what counts.
Does replacing a flat roof count as a major renovation under the county policy?
The text we read does not say. Policy i speaks of zoning proposals for adaptive reuse, major renovation or retrofit, and it does not define those words for a roof. Planning staff can tell you how they apply it.
My Chantilly building is in ZIP 20152. Does this reading apply?
Not necessarily. This page reads Fairfax County texts, and a ZIP 20152 parcel is under Loudoun County. Loudoun's green building wording is unread here. Confirm the county first.
Is TPO the usual roof on large Chantilly buildings?
No count of commercial roofs by material turned up, so we will not say. Ask the owner for the membrane name in writing.
Pages read
Which pages did we open for this Chantilly TPO guide?
Checked October 14, 2026.
- Fairfax County Policy Plan: Environment
- Fairfax County Comprehensive Plan: Dulles Suburban Center
- EPA: Using cool roofs to reduce heat islands
- Cool Roof Rating Council: FAQs
- 2021 International Building Code, chapter 15
Back to roofing in Chantilly. The same city's metal roofs page sorts by pitch. Nearby, Reston's TPO page and Fairfax's TPO page read their own sources. See all service areas or the roofing materials comparison.
Talk through the next step
Bring the building type and what is on the roof
Tell us the street, whether the roof is on a house, an apartment building or an office, and what you know about the membrane. A short phone call comes first.
9220 Topaz St, Fairfax, VA 22031
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