Why roofs fail
Damp does the work here, and it works slowly enough that most of it stays invisible until the wood gives.
- 1 Ridge caps. The first pieces to lift, and the ones the weather gets underneath.
- 2 The field. Moss on the damp slopes holds water where the covering wants to dry.
- 3 Valleys. Needles mat where two slopes drain as one, and stay wet for months.
- 4 Flashing. The chimney, and where an addition meets the original roof.
- 5 The vent boot. Rubber perishes quietly under a canopy that never lets it dry out.
- 6 Eaves. The last part of the roof to dry, and the first to go soft.
The six
What damp does, slowly
Eight damp months a year that grow moss on every shaded slope, and conifers that mat the valleys and gutters with needles. Winter condensation under the deck of any attic that cannot breathe — a ventilation problem, not a weather one. Edges that stay wet long after the field has dried. And flashing that outlives its sealant at every chimney and vent. All of it fails quietly, which is the difficulty.