Drone survey in Dorchester

The old centre sits on the Roman street grid with brick, flint and rendered frontages, Georgian and Victorian buildings and post-war estates around them. On the western edge, Poundbury has its own distinctive stone, slate and tile vocabulary, built recently but detailed in a traditional way.

That produces an unusual survey situation: modern buildings with traditional detailing. Parapets, valleys, stone dressings and complex roof forms on buildings that are only a couple of decades old. The details need looking at like old ones even though the fabric is new, and the workmanship question is a live one.

Rainfall here is well below Devon levels and the wind comes off open chalk ridges. Frost action on mortar in exposed ridge and verge details is the more usual issue, rather than the salt and gale damage that dominates the coast.

That changes what a survey looks for. Instead of lifted ridges and corroded fixings, the recurring findings are softened mortar, open joints and the slow opening of a detail that was sound when it was built.

Stone slate and thatch appear on the older fringes of the town, both traditional and both dependent on being kept dry. Thatch in particular is worth recording rather than diagnosing from the air: photographs show the ridge, the coatwork and the netting, and a thatcher judges the rest.

The water meadows and the downland around the town also mean a good share of enquiries are for farm buildings and rural properties rather than for the town itself.

Dorchester has room. Gardens, yards and open ground on the edges make take off positions easy, and the downland gives clear approaches for anything on the outskirts.

Maiden Castle and the surrounding scheduled landscape are planned around, which for ordinary domestic work in the town is not a factor at all.

As the county town, Dorchester generates a particular kind of enquiry: surveys wanted as evidence for somebody official. Planning applications, conservation queries, insurance questions and disputes all end up wanting a photographic record of a building as it currently stands.

For that use the report has to be careful and dated rather than persuasive. What was visible, on what day, in what conditions, and what could not be seen. A DT1 property in the conservation area is far better served by a plain record than by an opinion.

The Roman street grid also gives the older centre a tight, regular plan with narrow plots and buildings that meet each other on every side, so photographing one roof means being clear about where its neighbours begin.