Slate, tin and copper roofing in Georgetown (20007)

Georgetown is the one DC neighborhood where exterior work visible from a public street goes before the Old Georgetown Board, which advises the Commission of Fine Arts. A DOB permit alone is not enough for a front slope, a dormer or a new skylight that can be seen from the sidewalk. The board looks at material, profile, seam spacing and color, and it generally expects the original type to come back.

We plan around that from the first visit. We measure seam spacing on the existing metal, record the slate size and exposure and photograph every elevation that shows from Prospect, N or Dumbarton Streets. That record goes into the submission, along with product data for the replacement material, so the board sees a like-for-like job.

Many Federal houses near M Street and along the canal have shallow-pitched roofs of flat-lock or standing seam terne. When those roofs are painted every several years, they can last generations. When they are neglected, rust starts at the seams and around chimney bases, and pinholes let water into the attic.

Small rust spots get wire-brushed, primed and repainted with a metal roof coating. Open seams are resoldered. When the pan itself has thinned, we replace sections with new terne-coated stainless or painted steel, matching the seam height. Our metal roof repair page explains the soldering and patch methods we use.

A full new roof is usually standing seam metal formed on site to the original panel width, with seams locked by hand at the eaves where a machine seamer cannot reach.

Victorian houses along Q Street and up toward Georgetown University often have slate on the main slopes and copper on dormer cheeks, bay roofs and valleys. The slate itself can outlast several owners; the copper valleys, nails and flashings fail first. We replace slipped slates with copper hooks and rebuild failed valleys in 16-ounce copper.

Wood cornices and built-in gutters are the other sore spot. Water that overflows a clogged box gutter rots the cornice from inside, and the paint looks fine until the wood gives way.

When we open a cornice, we replace rotted blocking and fascia with matching profiles milled from clear lumber, then reline the gutter trough in copper with soldered seams and an expansion joint at each end. A box gutter relining done this way can go decades without attention beyond cleaning. We prime every cut end of the new wood before it goes back so the paint holds.

Narrow brick sidewalks, tight parking and few alleys make staging hard. We usually need a DDOT public space permit for a small hoist or scaffold, and we schedule deliveries for early morning before M Street traffic builds. Material comes up by hand or rope hoist in small loads, and debris goes down in bags rather than a chute.