Roof replacement in Washington, DC

We judge a roof by its deck and its flashing, not by how the surface looks from the sidewalk. A tired-looking covering can have years left, while a clean one can be failing at every wall joint. On a rowhouse we probe the membrane along the parapets and the rear wall, because that is where water reaches the joists first. On a pitched roof we lift shingle tabs near the eaves to see whether the mat has turned brittle.

The real question is whether repairs are buying time or chasing water. One failed seam gets a seam repair. Soft decking in three spots, grit piling in the gutters and patches stacked on patches usually mean a new roof costs less than the next five years of service calls. You see photos of everything we found before anyone talks numbers.

Some roofs sit right on the line. When that happens, we price a targeted repair of the worst areas next to the full replacement and tell you how long the repair should hold, so you can schedule the new roof for a season that suits your budget.

Washington housing falls into a few broad roof types, and each one points toward a different system. The classic rowhouse in Petworth, Bloomingdale or Columbia Heights has a low-slope roof hidden behind a brick parapet, draining to a rear gutter or a scupper. Those roofs want a membrane, usually in a light reflective color.

Victorian rowhouses and detached homes on Capitol Hill and in Mount Pleasant often pair a flat main roof with a slate mansard on the front and a small bay roof finished in tin or copper. That puts two or three systems on one building, and the transitions between them cause most of the trouble we see.

In upper Northwest, Bethesda and the Virginia suburbs, the usual house is a colonial, Cape Cod or split-level with a steep roof. Architectural shingles cover most of them, though slate, synthetic slate, standing seam steel and cedar shake each make sense for certain styles and for owners who plan to stay a long time.

• Low-slope rowhouse roofs: TPO, EPDM or two-ply modified bitumen
• Front mansards and turrets: natural slate or synthetic slate
• Bay roofs and porch roofs: standing seam steel or copper
• Steep suburban roofs: architectural shingles, slate or cedar shake

Tear-off tells the truth about a building. On older DC rowhouses we often uncover two or three layers of built-up roofing and silver coating over tongue-and-groove boards that have been damp for years. Everything comes down to the boards, the soft ones get replaced, and the deck is refastened tight before insulation or membrane goes back.

At the walls we cut out the old base flashing and run new flashing up the parapet and under the coping, or into a reglet cut in the brick. Chimneys on pitched roofs get new step and counter flashing. On low-slope roofs, every pipe, vent and hatch gets a proper boot or curb wrap instead of a smear of mastic.

Drainage gets corrected while the roof is open. Water that ponds against the rear wall calls for tapered insulation to push it toward the outlet. A new roof draining into a rusted scupper and downspout only relocates the leak, so we size and replace those at the same time.

Most roof replacements inside the District need a permit from the DC Department of Buildings, and we file it before the dumpster arrives. When the dumpster has to sit on the street instead of the alley or a driveway, a separate public space permit is required, and we handle that paperwork too.

Homes in historic districts such as Capitol Hill, Shaw, LeDroit Park, Mount Pleasant and Cleveland Park carry an extra step. Visible changes, like trading a slate mansard for another material, go through the Historic Preservation Office. A flat roof hidden behind a parapet rarely draws comment, but the street slope does, and our guide to DC permits and historic review walks through the details.

DC energy rules push reflective cool roof surfaces on low-slope replacements, so most rowhouse membranes we install are white or light gray. In Maryland and Virginia the county permit office handles approvals, and we confirm what each office expects before ordering material.

Access shapes the schedule more than most owners expect. Rowhouse jobs usually stage from the alley, with material lifted by hoist or passed up through the roof hatch when there is no room for a lift. We cover skylights, protect the neighbor's roof where our crew crosses the party wall, and tarp the yard so old gravel and nails stay out of the garden.

A typical rowhouse flat roof takes one to three working days. A shingle roof on a suburban colonial often runs two days, while slate and copper take longer because every piece is cut and fitted by hand. We never open more roof than we can dry in before dark, and we watch the radar closely during summer thunderstorm season.

Before we pack up, you get a photo set showing deck repairs, flashing details and finished drains. Keep those images with your house records, since the next buyer's inspector will ask what is under the new surface.