Drone survey in Totnes

The dense medieval and Elizabethan core has slate-hung and jettied frontages, with Georgian and Victorian streets around it and modern estates at Bridgetown and Follaton. In the old centre the buildings are not separate objects. They lean on each other, share walls and abut at odd angles, and the roofs meet in hidden valleys and secret gutters that were made by hand.

Those are the trouble spots. A hand-formed valley between two buildings of different dates, with a lead detail that has been patched twice, collects leaf litter from the trees on the hill and holds it. Nobody can see into it from the street and nobody can safely get to it from a ladder. From directly above it is simply visible.

Slate hanging on walls is a South Devon answer to driving rain, and Totnes has plenty of it. It works well and it lasts, but it conceals the wall behind, so a fixing failure or a damp problem underneath develops out of sight.

In photographs the clues are geometric: a run of slates sitting slightly proud, a course that has dropped a few millimetres, a dark line where water is tracking. Those are visible in a high resolution image and effectively invisible to somebody standing on a steep street looking up.

The town climbs hard from the river to the castle and the main street is a genuine hill. That makes ladder work awkward and scaffold expensive, and it means take off positions are often on a different level from the roof being photographed.

The upside is that a hillside gives an aircraft plenty of clear approaches. The usual plan is to work from above the property rather than below it, which also keeps the aircraft away from the busy street.

The valley is damp and the historic roofs trap debris, so problems here develop slowly and are usually well established by the time anybody notices. That suits a survey, because there is normally time to gather evidence and get quotes rather than react.

With listed and historic fabric, the record also supports the consent process. Describing what is there is half the work of an application, and photographs do that better than prose.

Beyond the town the Dartington estate and the farmland of the South Hams bring larger houses, barns and estate buildings into the same catchment, and those are typically surveyed as groups rather than singly.

For a TQ9 rural property the constraint is usually the lane rather than the building. Access for equipment is limited on the narrow roads around the estate, and that is the everyday practical argument for a survey that does not need a vehicle to reach the roof.

The tidal limit of the Dart also means the lower part of the town sits on ground that is damp for much of the year, which shows up in the same way it does elsewhere on the river: growth on shaded slopes and debris in valleys.