Slate Roofing in Stirling

Climb into the loft of a Stirling villa and you will see timber boards, not the underside of slates. That is sarking: a full deck of boards over the rafters, and it is the biggest difference between a Scottish slate roof and an English one. South of the border slates hang on thin battens with two nails each; up here they were nailed once, through the head of the slate, directly into the boards. The sarking stiffens the whole roof against wind and gave the house a second line of defence long before roofing membranes existed.

The slates were laid in diminishing courses, sorted by hand so the largest went nearest the eaves and each course above was a little shorter. It is why an old Scottish roof looks the way it does from the street, and why re-laying one is skilled work: every slate has to go back in the right course, on a roof that may have twenty different sizes on it.

Nail sickness is the reason these roofs eventually need attention. The single wrought-iron nail per slate corrodes, and once enough have gone the slates start to slide, often several at once after a gale off the hills. Earlier roofers will have hooked them back with lead tingles. When you can count those tingles by the dozen from the pavement, the roof is telling you its fixings have finished, even though the slate has decades left in it.

We put every Stirling slate roof we survey into one of three groups, and we photograph what we find so you can see why.

• Repair. A few slipped or broken slates, sound nails elsewhere, lead in reasonable order. We refix or replace with matching slate and you are done for a few hundred pounds. Most roofs under about a century old land here.
• Overhaul. One elevation, typically the one facing the weather, is nail-sick while the other is lying tight. We strip and re-lay the bad side, re-using its slates, renew the ridge and the leadwork, and leave the good side alone. It buys a long life for a fraction of a full re-slate.
• Full re-slate. Slipping everywhere, rust staining under the slates, boards you can push a screwdriver into. The roof is stripped to the sarking, rotten boards are replaced, a breathable membrane goes on, and the slates are graded, re-holed and re-laid with copper or stainless nails, topped up with matching reclaimed stock.

The lifespan question settles it. Scottish slate that is still hard and rings when tapped will do another 100 years, and we say so. Slate that is flaking into layers or soft at the nail hole is finished, and no amount of refixing will save it. Everything else on the roof, from nails to lead to membrane, is measured in decades; the slate is the only part measured in centuries, which is why it is worth spending money to keep. Our post on how long slate and tiled roofs last covers the warning signs in more detail.

Stirling takes its historic roofs seriously. The Old Town, King’s Park and Bridge of Allan are conservation areas, and many of their buildings are listed. In practice that means: like-for-like repair or re-slating in natural slate needs no consent; changing the covering to tile or fibre-cement slate, altering dormers or removing chimneys can need planning permission from Stirling Council, and on a listed building will need listed building consent. We tell you which applies before we quote rather than discovering it halfway through.

If you own a pre-1919 building within the city, or in Bridge of Allan, Dunblane or Blairlogie, it is also worth knowing about Stirling City Heritage Trust’s Traditional Buildings Health Check. Members get a low-cost independent inspection report that prioritises repairs and recommends traditional methods and materials. We are happy to work from those reports; they tend to ask for exactly the kind of like-for-like slate and lead repair we do anyway.

A King’s Park or Bridge of Allan villa can have five or six chimney stacks, several valleys, a run of dormers and a parapet gutter or two. Each is a junction, and junctions are where slate roofs leak. Stepped lead flashings, soakers behind them, valley linings and back gutters were fitted at the same time as the slate, so they are the same age, and lead does not last as long as good slate. When we re-slate, all of it is renewed as part of the job. When we repair, we check it while we are up, because it is often the real cause of the damp patch you rang about. Details are on our Stirling leadwork and Stirling chimney repairs pages.

Where your own slates can be re-used, they should be: they already match and they have proved themselves. Shortfalls are made up with reclaimed Scotch slate, graded to your courses. If a roof is being re-slated from scratch, or the original slate is beyond saving, the choice is between Welsh slate (the closest in quality and the most expensive), Spanish slate (uniform, reliable and the most common new natural slate in Scotland) and Brazilian slate (cheaper, with quality that varies by quarry). In a conservation area the council will usually expect natural slate of a similar size, colour and texture, and we bring samples to the survey so you can hold them against your roof. The Falkirk slate roofing page has more on how we source and grade reclaimed slate, and our gallery shows finished work.