Drone survey in Topsham

Topsham's historic core is a dense run of merchant houses and cottages, a great many of them listed, with Victorian and Edwardian streets behind and modern infill towards the Exeter road. The roofscape includes natural slate, clay pantile, lead and zinc detailing and the Dutch-influenced gables the town is known for, which is a lot of different materials meeting each other at a lot of junctions.

The awkward part is reaching any of it. The Strand and the lanes off it were laid out for carts, and a scaffold on a listed frontage is a planning conversation as well as a cost. That is the specific reason aerial photography took hold here early: it produces a close look at a gable, a parapet or a zinc detail with nothing standing on the pavement and nothing fixed to the building.

The town was built right up to the water on the west bank of the Exe estuary, with salt marsh and mudflats around it. Estuary air is damp and salt-laden all year, not just in storms, and the wind runs straight up the estuary from the south so that rain is driven hard at south-west facing slopes.

What that does to a building is mostly about fixings and metalwork. Nails corrode faster than inland, lead and zinc work harder, and any ferrous fixing on an exposed elevation has a shorter life than the same fixing three miles up the road in Exeter. Those are all small components that fail invisibly and are only obvious in a close photograph.

Tight. Take off ground is the first thing to solve, because many of the older properties have no off street space at all, and the answer is often a quayside space, a garden behind or a neighbour's yard with permission. That gets arranged in advance rather than found on the day.

The estuary itself is an advantage once the aircraft is up. There is open ground and open water on the eastern side of the town, so the standoff distances that are difficult inland are easy here, and elevations facing the water can be photographed from a position that does not sit above anybody's garden.

For a listed building, a photographic record has a use beyond finding a defect. Anybody applying for consent to repair or alter has to describe the existing fabric, and a set of dated images of the roof and the detailing is a better description than a paragraph. Conservation officers are looking at the same things a survey photographs.

It also matters for the reverse case. If a repair is refused or queried, the record of what was there before the argument started is worth having, and it is much easier to gather while nothing is urgent than during a dispute.