Drone roof survey in Lyme Regis

Lyme Regis is built on a coast that is actively unstable. The landslip geology that makes the fossil beaches famous is the same geology that moves under the town, and parts of it have moved measurably within living memory.

Ground movement shows up in a roof before it shows anywhere else that is easy to see. A ridge line that has developed a dip or a kink, a gable that has pulled fractionally away from the main slope, a chimney stack leaning a degree or two out of true: these are the early signs, and they are all above eye level.

That makes a flown survey unusually valuable here, because the imagery gives you a straight line to measure against. A ridge photographed from the air either runs true or it does not, and comparing this year against last year answers whether anything is still moving.

The town is built into the hillside and the streets are steep, narrow and often unsuitable for anything larger than a car. Getting a scaffold to a property on the upper streets is a genuine logistical exercise and getting one to a cottage on one of the lanes may not be possible at all.

The historic core is dense: cottages and Georgian townhouses packed tightly, roofs at every conceivable height relative to their neighbours, and slate hanging on the elevations that face the weather.

A flown survey works around all of that, and because it touches nothing it avoids the listed building question that applies to a large share of the older stock.

The town faces south-west with the sea at the foot of it, which is the full exposure. Salt reaches the lower town constantly and the upper slopes take the wind, so there is nowhere here that is comfortably sheltered.

The combination of salt corrosion on fixings and structural movement in the building is what makes Lyme a place where slates slip individually and repeatedly rather than a roof failing all at once. Fixing one slate at a time gets expensive, and knowing whether the pattern is spreading is what tells an owner when to stop patching.

Flat roofs on the cliffside extensions and terraces that are common here get the same treatment: membrane condition, ponding, and whether the upstand at the abutment is still sound.

The museum on the seafront, close to the Cobb, occupies one of the town's older buildings and stands as a reminder that ground movement here is not a hypothetical risk written up for planning documents: it is a fact the town has organised its own history around. Any survey of a nearby roof takes that context as read rather than as a surprise, which is part of why year on year comparison matters more in Lyme than in most of the towns this site covers.