Chapter 1: Why are the ridge tiles coming loose on our AWRE-era house in Tadley?
What we find
On the semis and terraces built for Aldermaston workers, the ridge (the row of capping tiles along the top of the roof) was set in a bed of sand and cement mortar. So was the verge, the edge of the roof at the gable end. That mortar has now taken more than half a century of frost, sun and rain, and it shrinks and cracks away from the concrete tiles. Once the bond goes, a ridge tile can rock in its bed and lift in a strong gust.
From the street, the first sign is often a scatter of mortar crumbs in the gutter or on the drive, or a ridge tile sitting slightly out of line with its neighbours. In the loft you may see daylight along the ridge board, or a damp stain on the timber below it. Because the estates were built in runs, the neighbouring roofs usually show the same fault at a similar stage.
What we fix
We lift a sample of ridge tiles first, to see whether the tiles are sound and only the mortar has failed, which is the usual finding on these houses. Sound tiles can go back on, but BS 5534 now requires ridge, hip and verge tiles to be mechanically fixed, with mortar no longer relied on by itself. So on Tadley's estate roofs we normally recommend dry-fix: the ridge tiles are screwed or clipped to a continuous batten over a breathable roll, and nothing depends on mortar holding. Dry-fix systems are covered by BS 8612.
Gable verges can be done at the same visit with dry verge caps, plastic units that clip over the tile ends and stop wind getting under the edge. Typical UK prices reported for a dry ridge on a semi run from £900 to £1,600, with scaffold at £300 to £900 on top; your fixed quote follows the survey. Our ridge tile repairs page explains the options in more depth.