Roofing terminology
Roofing Terminology: Spalling
- Spalling
- Spalling is the deterioration of brick or roof tiles where the surface layers flake, crack, or peel away. In UK roofing, it is primarily caused by freeze-thaw weathering, where absorbed moisture freezes, expands, and fractures the clay or concrete structure, necessitating urgent structural tile replacement.
Spalling often appears as powdery deposits, exposed aggregate, or sharp-edged fractures along tile ridges and eaves. On historic clay roofs, early intervention prevents water ingress that would otherwise rot battens and underlay.