How long does a tiled roof last?

The headline number for concrete interlocking tile is about sixty years, and that arithmetic is now uncomfortable for a lot of local housing. VOA data puts Weston at 80.3% built between 1945 and 1982, and much of the housing on the western and southern edges of the town is from the same era. Those roofs are at or beyond the age they were designed for.

That does not mean they all need replacing. What it means is that assuming a roof is fine because the tiles are intact is no longer safe, and a proper look — including from inside the loft — is worth having.

The reason is that concrete tile roofs fail from underneath. The tiles themselves are extremely durable in the sense of not breaking, but the nails corrode, the battens soften, and the underlay — nearly always a bitumen felt on roofs of this era — becomes brittle and tears at the laps and around the nail heads. From the street everything looks fine; from the loft it is a different picture entirely.

The tiles do age in one visible way. Concrete tiles are made with a coloured cement slurry finish, and that erodes over decades, exposing the coarser aggregate underneath and giving the roof a rougher, paler, chalkier look. That is cosmetic in itself, but a roughened surface holds moss and holds water, which matters where there is frost — and frost increases sharply with altitude across this patch.

Clay is a different proposition. A well-made clay tile will comfortably do sixty years and frequently a great deal more; roofs of a century are not unusual. The weakness of clay is frost damage in a porous or underfired tile, which delaminates in flakes off the face — and again, that shows up on the high ground east of the town more than in it.

This is also the roof type most heavily targeted by coating and spray sales, and the answer there is straightforward. A coating does not restore a worn tile and does nothing whatever about corroded nails or rotten battens, which is what actually ends a roof of this type.