Slate and ornamental terracotta — heritage roofs that punish the wrong approach
The defining feature of roofing in this pocket is that a meaningful number of the grander Edwardian and late-Victorian homes are roofed in genuine slate, and slate does not behave like tile. It fails by delamination — the stone splits along its natural bedding planes as water works in and freezes — and by nail sickness, where the fixings corrode and slates begin to slip while the stone itself is still perfectly sound. Neither problem is solved by coating. In fact, applying a membrane system to a slate roof is actively destructive: it traps moisture in a material that must breathe, and it is irreversible. The correct work is careful individual slate replacement with matched stock, re-fixing, and attention to the lead flashings and valleys that do most of the failing on these roofs. The same principle applies to the ornamental terracotta ridge cresting and finials found on Victorian rooflines here — those are heritage fabric worth preserving, and they need traditional repointing rather than replacement with modern profiles.
