Storm damage roof inspection in Tavistock

Tavistock sits in the Tavy valley on the western edge of Dartmoor, with the moor rising immediately east and the Tamar valley falling away west towards Cornwall. Being this close to high ground means Tavistock sees wet weather, with Dartmoor to the east and the prevailing south-westerly bringing rain straight up the Tamar valley in a storm, a combination that produces sustained heavy rainfall on top of whatever wind the same front is carrying.

Steep sites around the town, a natural consequence of a valley settlement, mean many roofs sit at awkward angles to the prevailing wind, and the tall stone chimneys that are a feature of the town's granite and Hurdwick stone architecture carry a specific wind-loading risk that a simpler modern chimney does not: more mass, more surface area, and a long lever arm acting on the roof structure beneath in a strong gust.

Tavistock Abbey's surviving remains, close to the Pannier Market at the centre of town, are a reminder of how long buildings here have had to cope with the same wet, funnelled weather, and the River Tavy running past them is usually the first visible sign of how much rain a given storm has actually delivered.

The Victorian planned centre in green Hurdwick stone, built on the wealth of the surrounding mining industry, carries Delabole slate on stone-bedded ridges rather than the mortar bedding more common elsewhere in Devon, a construction detail that behaves differently under storm loading and needs checking on its own terms rather than assumed to fail the way a standard ridge would. Georgian survivals and terraced miners' cottages in the surrounding villages see more conventional slate and ridge failure.

Modern estates on the fringes of the town run concrete tile, and see the straightforward ridge and verge pattern common to exposed inland sites without the added complication of stone-bedded ridge detailing.

Because a tall stone chimney under wind loading can move or crack in ways that are not obvious from the ground, a flown survey that gets close, referenced detail on the stack itself, not just the surrounding roof plane, is worth more here than on a town where chimneys are smaller and lower.

Stone-bedded ridges on the town centre's Delabole slate roofs need the same close attention, since a storm can disturb bedding of this kind without dislodging a whole tile, leaving a defect that is hard to see from a passing glance at street level.

The Cornwall and West Devon Mining World Heritage Site designation covers a good deal of the ground around the town, a reminder of how much of Tavistock's stone building stock, including the tall chimneys mentioned above, was built on mining wealth within the PL19 postcode area. Okehampton, along the moor edge to the north, takes an even wetter version of the same Dartmoor weather.