Why roofs fail
Ask anyone who repairs roofs where they leak and the answer is the same: not in the middle, but wherever the roof meets something else.
- 1 The ridge. The highest course, and on slate the one most often reset by hand.
- 2 The field. Slate on the older stock, shingle on the rest. Two very different clocks.
- 3 Valleys. Where leaf litter settles, and where a slate roof usually ends its life.
- 4 Wall flashing. The party wall of a row or twin, rising through a roof two houses share.
- 5 Penetrations. Holes cut on purpose. When access is awkward they get sealed instead of rebuilt.
- 6 The overhang. Where meltwater from a warm attic reaches cold framing and stops.
The six
What this region does to a roof
A winter that hovers at freezing and crosses the line dozens of times, working on every seam. Capes and split-levels with finished rooms in the roof, leaving knee-wall pockets that cannot be ventilated like an attic. A second layer of shingles hiding a deck nobody has seen in forty years. Skylights and dormers whose flashing was sealed rather than layered. Roof planes that stop against a wall. And a fascia edge quietly going soft behind the gutters. Most of what ends a roof here traces back to one of those.