Del River Roofing

Why roofs fail

Century-old slate reaching the end of its life street by street, and party walls where two houses share a single joint.

An old roof rarely gives out in the field. It gives out at the joints and the edges. Six failure points on housing that mostly predates the shingle.
Garage Point 1: ridge caps 1 Ridge caps: thin, exposed, first to lift Point 2: the field of the roof 2 The field: slate or shingle, aging Point 3: valleys 3 Valleys: litter holding the water Point 4: flashing 4 Flashing: masonry, party wall Point 5: vent boot 5 Vent boot Point 6: eaves and ice dams 6 Eaves: where the porch roof meets the wall
  1. 1 Ridge caps. Thin, fully exposed, and usually the first course to let go.
  2. 2 The field. Slate on the older rows, shingle on the rest, each on its own clock.
  3. 3 Valleys. Two slopes emptying through one line, with litter holding the water there.
  4. 4 Flashing. Old masonry, and the party wall a rowhouse shares with the house next door.
  5. 5 The vent boot. A small rubber part with a far shorter life than the roof it sits in.
  6. 6 Eaves. Where the porch roof ties into the wall, and where backed-up water gets in.

The six

A century of building, and what it left behind

Slate laid a century ago, reaching the end of its life street by street. Porch roofs too shallow for the shingle someone put on them. Party walls where two houses share one flashing joint. Valleys buried under a mature canopy every autumn. Chimney counter-flashing caulked to old brick instead of cut into it. And attics that were never built to breathe. Old roofs fail at their details, and those are the details.

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