Reston's modernist roofs
Robert E. Simon commissioned prominent modernist architects to design Reston's early townhouse clusters. As Washingtonian described in 2017, Charles M. Goodman's Hickory Cluster near Lake Anne was designed in the International style with flat roofs and walls of glass, and Chloethiel Woodard Smith's Coleson Cluster is a series of flat-roofed townhouses with floor-to-ceiling windows. Smith also designed Waterview Cluster, where, according to the cluster's own history, roof design mattered enough that she used a variety of roof colors and contours to create a pleasing view from higher ground.
Not every contemporary Reston home has a flat roof. Many have conventional pitched roofs with modern massing, and plenty of later homes are traditional in style. But flat and low-slope sections show up more often here than in a typical Northern Virginia subdivision, on main roofs, porches, additions and connecting links.
Why shingles have limits
Asphalt shingles shed water by overlapping: each course laps over the one below, and gravity does the rest. On a steep roof that works well. As the slope flattens, water moves more slowly, wind can push it uphill under the laps, and standing water has time to find a way in. Shingle manufacturers publish a minimum slope for their products, often with extra underlayment requirements near the bottom of that range. Below it, a shingle isn't the right material.
Truly flat roofs and very low slopes use continuous membrane systems instead of overlapping pieces. Reston Association records show the kinds of materials that come up: February 2024 DRB minutes, for example, record an approved screened porch with an EPDM membrane roof. The right system depends on the slope, the structure, what's there now and what your guideline or cluster standard allows.
What matters most on a flat roof
- Drainage. Flat roofs aren't perfectly flat; they rely on slight slopes toward drains, scuppers or edges. Ponding water that sits after rain is a sign something has settled or is blocked.
- Edges and walls. Where the roof meets a parapet, a wall of glass, or a higher roof, the flashing and termination details do most of the waterproofing work.
- Penetrations. Vents, flues and skylights through a flat roof need flashing designed for that roof type, not shingle-roof parts.
- Shared roofs. In a townhouse row, roofs may run continuously across units. Where your section ends and how it ties into a neighbor's needs to be clear before work starts.
- Insulation and ventilation. Many flat roofs have little or no attic space, so moisture control is part of the design rather than an afterthought.
A Roofing Roughnecks flat roof repair over a covered porch and balcony in Oakton, before and after views of the same home.
Keeping the original look
On a modernist house, the roofline is part of the design: thin edges, crisp fascia, consistent color seen from above. Reston Association reviews roofing for compatibility with the house and its architecture, and cluster standards in the older clusters are often written to preserve the original character. Waterview's standards, for example, prefer matching each home's original 1964 roof color and ask that metal flues be painted the roof color. Before you change the edge profile, the color or the material, check your standard and expect review.
How we approach these roofs
Roofing Roughnecks assesses flat and low-slope sections case by case. We look at slope, drainage, edges, penetrations and how the section ties into the rest of the house, then tell you plainly what we recommend and whether it's work we do. The division's confirmed product list is GAF and CertainTeed shingles and Leaf Relief gutter guards, so if a roof needs a specialty membrane system or a product your cluster names that we don't install, we'll say so rather than force a shingle onto a roof that shouldn't have one.
Mixed roofs are common: a pitched main roof with a flat porch or a low-slope connection. In that case the shingled areas, the low-slope areas and the transition between them all belong in one written scope, so nothing falls between trades.
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Related pages
Can I put shingles on my flat roof?▸
Not on a truly flat roof. Shingle manufacturers set a minimum slope for their products; below it, a membrane system is the appropriate choice.
Water sits on my flat roof after rain. Is that a problem?▸
Standing water that lingers points to a drainage issue: settled framing, a blocked drain or scupper, or built-up debris. Have it looked at before it finds a seam.
Do I need Reston Association approval to change my flat roof's color?▸
Changing the color or material of a roof generally needs review, and older clusters often have standards meant to preserve original colors. Check your cluster standard and ask your covenants advisor.
Do you replace flat roofs?▸
We assess flat and low-slope sections case by case and will tell you plainly whether a roof needs a system or product outside what we install.