Drone roof survey in Totnes

The historic core of Totnes runs up a very steep main street, and the buildings on it are medieval and Elizabethan in origin with later frontages laid over the top. What that produces at roof level is a dense, irregular arrangement of planes at different heights, meeting at angles that were never drawn on any plan.

Where one roof is higher than its neighbour, it discharges onto the lower one, either deliberately through a lead flashing or accidentally because a detail has failed. Working out which is happening is often the whole job, and it cannot be done by looking at one building in isolation.

Hidden valleys and secret gutters between adjoining properties are common. They collect leaf litter from the mature trees around the castle and the Dart, and once blocked they overflow inward into the wall head rather than outward where anyone would see it.

Slate hanging on walls is everywhere in the old town, protecting timber framing and rubble stone from driving rain off the Dart valley. It is a functional weatherproofing layer, not decoration, and when it starts failing the structure behind it begins taking water directly.

Judging a hung elevation from the pavement is close to impossible because you see it edge on, and the slates that matter are the ones under the overhang and around the window heads. From the air, at an angle, the condition is obvious in one frame.

Jettied upper floors add another complication: the roof above overhangs the wall below, so water shed from a failing detail lands somewhere unexpected, often on a neighbouring roof or into a gutter that was never sized for it.

A large proportion of the old town is listed and the whole centre is a conservation area, so any physical access to a roof is a conversation before it is a job. Scaffolding on the main street is also a serious imposition on a narrow, busy, steeply graded road.

A flown survey touches nothing, needs no ties into historic fabric, and does not close a street. For a listed building it is often the only proportionate way to answer a question about roof condition, particularly when the answer might turn out to be that nothing needs doing.

Outside the centre, the modern estates at Bridgetown and Follaton are conventional concrete tile, and the surrounding South Hams farmland brings the usual mix of farmhouses, barn conversions and outbuildings at the end of long tracks.

Dartington Hall and its estate sit just outside the town on ground more sheltered than the exposed hilltop streets around the castle, and the estate's older buildings carry a mix of stone slate and clay tile that has been repaired piecemeal over a long period. Piecemeal repair is worth flagging on its own: a roof mended in several different decades by several different hands rarely has one consistent standard of detailing, and the join between one repair and the next is where a survey usually finds the fault.