Roof repair in Thornbury

Thornbury and Clarksburg have a lot of genuinely old housing, and old houses fail differently than new ones. On a twenty-year-old subdivision home, a leak usually means the shingles are worn out. On a century home, the shingle field is often the newest and healthiest part of the roof, and the water is getting in somewhere the shingles never covered.

The usual suspects are chimneys, roof-to-wall junctions where an addition meets the original structure, and the transitions between roof planes on houses that have been added to more than once. Brick chimneys are the biggest single source. Mortar joints degrade, the counter-flashing that should be let into a mortar joint has often been surface-caulked instead, and once that caulk fails the water runs straight down the outside of the chimney and into the house.

We also see a fair amount of old galvanised flashing that has simply reached the end of its life. It was good material and it lasted decades, but it does not last forever, and replacing it properly means lifting shingles rather than smearing sealant over the top.

Some Thornbury roofs still carry original slate or cedar, or a later asphalt roof laid over details that were designed for those materials. Repairing them takes a bit of care. Slate is brittle underfoot and individual slates can be replaced without disturbing the field if you know how; walking it like an asphalt roof will cost you far more slates than the one you came to fix.

Where a heritage roof has been asphalt-shingled at some point, the details often did not get updated to match. Original roofs relied on generous overhangs, open valleys and steep pitch to shed water; modern shingles rely on underlayment and sealed laps. Mixing the two assumptions is where the leaks come from, and the repair is usually about correcting a detail rather than replacing an area.

If your property is in a designated heritage area or you are unsure whether it is, tell us before we quote. It can affect what is allowed, particularly if a repair turns into a visible material change.

Thornbury sits where the Beaver River meets the bay, and the exposure is genuinely different a few streets apart. Properties near the harbour take wind straight off the water; places up the valley get less wind but hold snow longer and see more freeze-thaw cycling as cold air drains down the valley overnight.

That matters for repairs because it changes what fails first. Near the water we see more mechanical wind damage: lifted tabs, loose ridge caps, torn flashing. Up the valley we see more ice-related damage: backed-up water under the eaves, split fascia, eavestrough pulled loose by ice weight. Same town, different repair.