Slate and tile restoration | Thornbury Slate & Copper

Stewardship

The roof will outlast us. So we write it down.

Every roof closes with a bound record and a crate of matched spares in the attic, so a broken slate in twenty years is replaced with one from the same lot.

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Roof recordNo. 41 · sample

Quarry: Vermont, unfading gray
Lot: 0917-B
Size and thickness: 18 × 10 in, 3/16 to 1/4 in
Exposure: 7.5 in, graduated to 6 in at the ridge
Fasteners: Copper nails, two per slate
Flashings: 16 oz copper, open valleys 5 in
Attic stock: 1 crate, 160 slates, north attic

Thornbury Slate & Copper

A slate roof usually fails at its metals before its stone: nails rust, flashings split and valleys wear through. Replacing those, and the broken pieces, often gives a roof decades more.

Matching

We match slate from the original quarry when it still runs, or from salvage stock we keep by color and size. Clay tile is matched from salvage or fired to match.

In writing

Every restoration ends with a written opinion on what is left in the roof, so the decision to replace is never made on a guess.

Questions about old roofs

Can my house carry slate or clay?

Many older Dallas houses were built for it; many newer ones were not. Slate and clay weigh three to five times a shingle roof, so a structural engineer reviews the framing before we order.

Do you repair old slate roofs?

Yes. A slate roof with broken pieces or failed flashings is often decades from replacement. We match slate from salvage or the original quarry when it is still running.

Why copper nails?

A slate can outlast a steel nail. When the nail goes, the slate slips. Copper lasts as long as the stone.

Will the copper turn green?

Bright copper goes brown within months and, in our climate, takes many years to show green. If you want the patina now, it can be ordered pre-patinated.

Many old slate roofs need flashings, not replacing.

The roof will outlast us. So we write it down.

Matching

In writing

Questions about old roofs

We begin with a walk of the roof and a measured drawing.