Chapter 1: Why is mortar dropping from the ridge and gable edges of our Binfield estate house?
What we find
On the estate houses built as Binfield spread out towards Bracknell, the ridge (the row of capping tiles along the top of the roof) was bedded in sand and cement. The verge, where the roof finishes at a gable wall, was bedded the same way. Years of frost, heat and rain make that mortar shrink and let go of the concrete tiles. Once the bond fails, a ridge tile can rock in its bed and a strong gust can lift it clear.
The first signs are usually crumbs of mortar in the gutter or on the driveway, or a ridge line that no longer looks straight from the road. Inside the loft you may see a thread of daylight along the ridge board or a damp mark on the timber below it. Neighbouring houses in a run were often built together, so the same fault tends to show on the whole row.
What we fix
We lift a few ridge tiles first, to learn whether the tiles themselves are intact and just the mortar has gone. That is the usual finding. Sound tiles can go back, but the current standard, BS 5534, wants ridge, hip and verge tiles held down by screws or clips, and a mortar bed on its own no longer counts. So we normally recommend a dry-fix system, where ridge tiles are fixed by screws or clips to a continuous batten over a vented roll, and nothing depends on a bed of mortar. BS 8612 covers dry-fix systems.
Verges can be done on the same visit with clip-on dry verge units that stop wind getting under the tile ends. The ridge tile repairs service page lays out the alternatives. Across the UK a dry ridge on a semi is typically reported at £900 to £1,600, with scaffold adding £300 to £900. Your fixed quote follows the survey.
