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PVC roofs in Washington, DC: who signs for the roof, and what has to sit under the sheet
A PVC membrane is a decision for a person or a board before it is a product. This page counts who owns and who rents in District buildings of each size, using the Census 2020 to 2024 five-year table of tenure by year built by units in structure, then turns to the part of a PVC roof that is specific to PVC: the insulation and cover board below the sheet, read from a federal guide specification and a Building America Solution Center guide, a U.S. Department of Energy program.
- 144,412 renter homes sit in buildings of 5 or more units
- 72,305 of 88,655 owner-occupied one-unit homes were built before 1960
- A federal PVC guide says not to adhere PVC directly to polystyrene
Three buildings, three signatures
Before a membrane is chosen, someone has to be able to say yes. In the District that person changes with the building, and so does the office that receives the paperwork.
The rowhouse
The owner signs. The Department of Buildings Homeowner Center helps owners of one- and two-family homes, and its list includes roof repair or replacement with no structural change. Applications for these homes go through the Permit Wizard.
The apartment building
The landlord signs for a rented building. For owner-occupied units the association documents decide, and the Census table does not show whether a building is a condominium or a co-op. Commercial projects use the Citizen Access Portal.
The commercial building
The building owner signs, and commercial permits use the Citizen Access Portal as well. No housing table speaks for these roofs, so the scope comes from the drawings and the owner.
A historic address adds a second reader. The Homeowner Center page says a property in a historic district applies for a Historic Property Special Permit, since the Office of Planning must review the scope. The Washington, DC roofing guide walks through that path; this page stays with the building stock and the layers below the membrane.
The Census count by building size
Table B25127 in the American Community Survey 2020 to 2024 five-year estimates crosses tenure with year built and units in structure for the city of Washington. It counts 324,491 occupied homes: 134,683 owner-occupied and 189,808 renter-occupied. Summed across all build years, the size classes look like this.
| Units in structure | Owner-occupied homes | Renter-occupied homes |
|---|---|---|
| 1, detached or attached | 88,655 | 20,650 |
| 2 to 4 | 8,220 | 24,545 |
| 5 to 19 | 10,529 | 37,467 |
| 20 to 49 | 8,075 | 16,964 |
| 50 or more | 19,167 | 89,981 |
Census Reporter copy of B25127, ACS 2020 to 2024, opened October 24, 2026. Column sums by the author; mobile homes and similar are left out, so totals differ from the headline by a few homes. Each figure is an estimate with a margin of error.
Read the owner column as people who each sign for a roof or a share of one, and the renter column as tenants whose landlord signs. A one-unit home can be a rowhouse or a detached house, and the table does not separate them, so it cannot tell you how many flat roofs there are.
How old the buildings are
Owner-occupied, one unit
50,540 were built in 1939 or earlier and 21,765 between 1940 and 1959. That is 72,305 of 88,655, or 81.6 percent, built before 1960. For these owners a roof decision arrives together with older deck, parapet and drain details.
Rented, 5 or more units
46,759 renter homes sit in buildings from before 1960, 30,581 from 1960 to 1979, 12,381 from 1980 to 1999 and 54,691 from 2000 on. A building from the newest group has a different deck and insulation history from a rowhouse, so the membrane question is not the same one.
Among owner homes in buildings of 5 or more units, 11,164 were built in 2000 or later. The Census figures are author arithmetic on the table cells, not a count of roofs.
The Office of Planning roof guideline notes that adding insulation may cause roof materials to deteriorate if it is not properly installed. That sentence is why the layers below the sheet get their own section next.
The layers beneath a PVC sheet
The Department of Buildings and Office of Planning pages read for this guide do not name PVC. The most specific neutral text is UFGS 07 54 19, Polyvinyl-Chloride Roofing, a guide specification used for federal work and revised in August 2023. It is not District law. It is a written record of what designers of large public roofs are told about PVC, and it speaks to insulation more directly than a general code does.
PVC membrane roofing should not be adhered directly to polystyrene
UFGS 07 54 19, designer note- Insulation first, in layers. The guide calls the preferred norm a minimum of two layers of rigid board insulation under the PVC, with an exception for garden-style roofs.
- Reinforced sheet. Adhered and mechanically fastened PVC systems use reinforced membrane, with a narrow exception for prefabricated detail flashings.
- No contact with asphalt. Reinforced PVC is not placed in direct contact with asphalt, coal tar pitches or petroleum-based products.
- One supplier chain. Insulation and facer must be compatible with the membrane, approved and supplied by the membrane manufacturer, and the submittals carry that manufacturer written acceptance.
- Heavier attachment at the edges. The designer note says the insulation may need to be adhered or fastened to the deck more often at corners and perimeter, and sometimes throughout the field.
Insulation types and what the sources say
Two neutral sources are set side by side. The guide specification is PVC-specific. The Building America guide covers single-ply membranes in general, so it names materials without a PVC rule. Where a cell reads silent, the source says nothing on that point.
| Layer | UFGS 07 54 19 (PVC) | Building America low-slope guide |
|---|---|---|
| Polyisocyanurate | Not named in the designer note. Insulation and facer must be compatible with the membrane and supplied by its maker. | Named among the rigid layers in an above-deck assembly. |
| Polystyrene (expanded or extruded) | Do not adhere PVC directly to it. The manufacturer verifies the system. | Extruded polystyrene is named among the rigid layers. |
| Perlite and standard wood fiber board | Do not adhere PVC directly to them. | Silent. |
| Cover board | Glass mat or moisture resistant gypsum roof board may sit above the insulation for wind, impact and hail resistance. | Plywood or OSB as an upper covering board; the single-ply may be attached or adhered to the insulation or cover board. |
| Asphalt, coal tar, petroleum products | No direct contact with reinforced PVC. | Silent. |
The guide specification does not split polystyrene into expanded and extruded boards, and it does not say what separator or facer makes a combination acceptable. That answer comes from the membrane manufacturer, in writing, for the exact products on your roof.
One more PVC-specific detail sits at the drains. The guide calls for a tapered insulation sump at each drain, with a slope not over 1:12 for reinforced membrane, and says to avoid field seams within 24 inches of a drain. It also calls for a test of surface dryness under ASTM D4263 on a concrete deck. For the membrane itself, the PVC roofing guide has the overview.
Seven lines for a PVC scope on paper
Each person in the first section can use the same list. The owner of a rowhouse keeps it in the job file. A board attaches it to the vote. A commercial owner attaches it to the drawings.
- The insulation boards are named by type and facer, with the membrane manufacturer written acceptance of that exact pairing.
- If any polystyrene, perlite or wood fiber board is used, the scope says what sits between it and the PVC and who approved that.
- The cover board is named by material, and the scope says why it was chosen.
- The number of insulation layers is stated, along with how the layers are attached at corners and perimeter.
- Old asphalt or coal tar layers that remain under the new sheet are listed, with the separation detail.
- Each roof drain has a tapered sump described, and field seams are kept away from it.
- For a historic address, the scope records that the Office of Planning was asked about the work.
Book a phone consultation to talk through a Washington, DC PVC roof; the call starts with the address, the building type, who signs for the roof and what is visible from the street. For flat roofs in general read the flat roof guide, and see roofing materials, roof replacement, commercial roofing and services. The District roofing hub sets out the permit and review path.
Where each figure came from
Opened October 24, 2026. Census sums are the author arithmetic on the table cells. The guide specification is a federal document and is not a District requirement.
- Census Reporter: B25127, tenure by year structure built by units in structure, Washington city, ACS 2020 to 2024
- Unified Facilities Guide Specifications 07 54 19, Polyvinyl-Chloride Roofing (August 2023)
- Building America Solution Center: Low-Slope (Flat) Roofs
- DC Department of Buildings: Homeowner Center and How to Get a Permit
- Office of Planning: Roofs on Historic Buildings (PDF guideline, undated)
Questions people ask
Who decides on a PVC roof for a District rowhouse?
The owner does, unless the house is in a historic district or the lot belongs to an association. The Department of Buildings Homeowner Center serves owners of one- and two-family homes and lists roof repair or replacement with no structural change among its jobs. For a historic property it says to apply for a Historic Property Special Permit, because the Office of Planning reviews that scope.
Who decides in a DC apartment building?
The Census table counts renters and owners but not the form of ownership, so it cannot say how many of the 37,771 owner-occupied homes in buildings of 5 or more units sit in condominiums or co-ops. For those, the governing documents of the association say who approves a roof. For rented buildings, the landlord decides, and 144,412 renter homes are in buildings of that size.
Can PVC be glued straight onto any rigid insulation?
Not according to the federal guide specification for PVC roofing, UFGS 07 54 19. A designer note says PVC membrane should not be adhered directly to polystyrene, perlite or standard wood fiber insulation, and that the membrane manufacturer must verify the compatibility of the whole system. Polyisocyanurate is not named in that note, so ask which facer the manufacturer accepts.
Does the guide specification say anything about a cover board?
Yes. It says glass mat and moisture resistant gypsum roof board can be used as an overlayment above the insulation to improve wind, impact and hail resistance. The Building America Solution Center guide, a U.S. Department of Energy program, describes a different cover board, plywood or OSB, in its single-ply assemblies.
Why does asphalt matter on a PVC roof?
The same guide specification says not to use reinforced PVC membrane in direct physical contact with asphalt, coal tar pitches or petroleum-based products. On a District roof that already carries a built-up layer, the question for a roofer is what separates the old material from the new sheet, and who confirmed it.
Does the Census say how many District commercial buildings have flat roofs?
No. B25127 counts housing units, not offices, shops or institutions, and it does not record roof shape. Commercial permits go through the Citizen Access Portal, and a commercial owner should expect the scope of a PVC roof to be set by the building drawings, not by a housing statistic.
Does a PVC roof need a thicker insulation layer at the drains?
The guide specification calls for a tapered insulation sump at roof drains, with a slope not over 1:12 for reinforced membrane. It also says to avoid field seams within 24 inches of a drain. These are federal specification details, not District code, so ask your roofer how the plan handles each drain.
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.