Thermal imaging survey in Topsham

Almost everything in Topsham's historic core predates cavity construction by a century or more. The merchant houses along the Strand and Fore Street are solid brick or stone, often rendered, with Dutch-influenced gable ends and roof planes that meet at odd angles from later additions bolted onto earlier buildings. There is no cavity anywhere in this stock, so improving it is a conversation about internal or external wall insulation, breathable materials on a listed building, and managing the risk of trapping moisture inside a wall that has traditionally been allowed to dry out.

That last point matters more here than almost anywhere else in the network, because a high proportion of these houses are listed, which changes what can physically be done about a thermal finding. Knowing where the heat is actually leaving the building, rather than guessing, is what lets an owner and a conservation officer have a useful conversation about a targeted fix instead of a blanket one.

Topsham sits on the water on three sides, and the air is damp and salt-laden all year, not just during storms. Solid walls in this position rarely get the chance to dry out fully, and a permanently damp wall conducts heat noticeably faster than a dry one, so a thermal survey here is reading a building that is working harder to stay warm than the same house built a few miles inland.

The wind has a second effect worth knowing before booking: there is a clear run up the estuary from the south, and driving rain on that exposure keeps the seaward faces of the old merchant houses wetter for longer after a storm than the more sheltered elevations, which is exactly the kind of local detail that changes when a flight should go up rather than whether it should.

Much of the old town is unsuitable for scaffolding or an external survey rig, the Strand and the lanes off Fore Street are narrow and parking is contested, so a flown thermal survey reaching the gable ends and roof planes without a pole or a ladder going up matters twice over here: once for practicality and once because nothing goes against historic fabric that a conservation officer would otherwise need to be consulted about.

A dawn flight after a cold, still night is the usual choice, timed to fall after the estuary's damp air has had a chance to settle rather than during an active blow, when the wind itself would disturb the reading before it disturbs anything else.

Down towards Bowling Green Marsh and the Goat Walk, the last houses before the water sit closest to the estuary's daily tide, and it is here that a damp solid wall shows its effect most clearly, a ground floor that never quite loses its chill even with the heating running hard. A survey covering one of these riverside properties is planned with the tide table in mind as much as the weather forecast, since a flight timed against a rising tide can catch the very conditions that make the wall's dampness, and its heat loss, most visible on camera.