Chapter 1: Why does our clay-tiled cottage in Sherfield-on-Loddon lose tiles after every hard frost?
What we find
Old plain clay tiles are porous. A tile that has soaked up water over a wet autumn can freeze in January, and the ice pushes the face off in flakes, which roofers call spalling. Once the face has gone, the tile thins, cracks across the nail hole and slides out of its course. You find the pieces in the border or on the path, and a gap that lets rain onto the battens below.
Timber-framed houses add a second cause. The frame has moved over centuries, so the roof planes are rarely flat, and tiles on a sagging section sit unevenly and shed water badly. From the loft you may see daylight through a slipped tile, or a dark stain on an old rafter where a leak has dripped for a season or two.
What we fix
We strip only the section that has failed and keep every tile that is still sound. The gaps are filled with salvaged or hand-made plain tiles chosen to match colour and curve, so the repair does not show from the lane. Rotten battens are replaced, and fresh nails or clips fix the tiles instead of the corroded ones that were holding them before.
We do not straighten a sagging roof plane unless it is leaking, because forcing an old frame to a new line can create more trouble than it solves. Where a bigger section needs replacing, we photograph the whole roof and talk the options through with you before you approach the conservation officer, since swapping the material could need the council's consent. Our pitched roofing page explains how this kind of work is planned.