Mansard, parapet and flat roof repair in Shaw (20001)

Brick parapets rise a foot or two above the roof on most Shaw rows, and their tops take the full force of weather. When the stone or terra cotta coping cracks, or the mortar under it washes out, water soaks down through the brick and shows up as peeling plaster on an inside wall, often far from the roof.

On blocks around 6th, 8th and 9th Streets NW, we regularly find copings set in failed mortar with no flashing beneath them. We lift the coping, repoint the top courses, install a through-wall flashing or a membrane cap and reset the stone. Where the coping is missing or broken, a formed metal cap is the practical replacement on rear walls. Our parapet and coping repair page goes into the steps.

Leaning or bulging parapets need masonry work before roofing. We tell you when a wall should be rebuilt rather than flashed.

The steep front roofs on many Shaw rowhouses are clad in slate or pressed metal shingles, with dormers punched through. Their weak points are the hip and ridge flashings where the mansard meets the flat roof, and the dormer cheeks where water runs down the side of the window box.

We repair these with matching slate or metal shingles and new copper step and apron flashing. Full mansard roof repair includes checking the hidden gutter at the base, which is often lined with old tin.

Pressed metal shingles, often in a diamond or scale pattern, were a cheaper alternative to slate on many of these blocks. They rust from the back where condensation collects, so a mansard that looks solid can be thin underneath. We pull a few pieces to check, and when replacements are needed we source matching patterns from salvage or from makers who still stamp them. Paint goes on after the repair so the patch and the original weather together.

Shaw has its own historic district, and Blagden Alley and parts of the Logan Circle area nearby carry their own designations. Changes visible from the street, like new mansard material, copings or rooftop additions, need preservation staff sign-off along with the DOB permit. Flat roofs hidden behind the parapet usually move more simply.

We photograph each elevation, record what is there and write the scope to put back matching materials. That keeps the filing short and the schedule predictable.

Because we are close by, an active leak near the Convention Center or the Howard Theatre can usually get a temporary seal within hours. We cover the failed area with a membrane patch or weighted tarp, clear the scupper and come back for the permanent fix once the roof dries. Before we leave, we photograph the patched spot so you can show it to your insurer if the ceiling needs work. Street parking near the 7th Street corridor is tight, so we use alleys like Blagden and Naylor Court where we can.