Slate With a Century Behind It: What Cupa Pizarras' New Guarantee Means for Exeter Roofs

A customer in Kingsteignton rang us last week after a survey turned up cracked slates and slipped nails on a roof that's barely twenty years old. It's a familiar story around Exeter and Chudleigh, where a lot of the older housing stock got re-roofed in reconstituted or lower-grade slate during the nineties, and it's now on its way out well before it should be. So it was good timing to see Cupa Pizarras, one of the big natural slate quarry operators supplying the UK, announce a 100-year guarantee across its whole range this month.

What makes it worth mentioning to customers is where that guarantee comes from. Cupa owns its own quarries in Spain rather than buying slate in from a third party, so the assurance is coming straight from the people who extracted and graded the stone, not a merchant putting their name to someone else's material. For us as installers, that traceability matters more than people realise — a slate that's inconsistent in thickness or has hidden lamination faults will fail at the nail hole long before its face wears through, and you don't always see that until you're up there stripping the old covering.

On a typical re-roof we're working to a batten gauge set for the slate size, usually around 100mm lap for a standard 500 x 250mm Welsh or Spanish slate, double-lapped and fixed with copper or stainless nails, never galvanised, because galvanised corrodes from the inside out under slate and you'll be back within fifteen years. Breather membrane goes down first with a minimum 150mm lap at the joints, and any valleys get Code 4 lead rather than a mineral-felt liner, which on a Devon roof catching the weather off the moor will outlast the slate itself.

We're licensed for asbestos containing roofing products too, which comes up more than you'd think on the older bungalows around Chudleigh and Kingsteignton with cement slate or corrugated outbuildings — that's a separate job with its own removal and disposal rules, and not something to leave to a general roofer without the ticket for it.

If your roof's slate is starting to slip, delaminate, or you've had a leak follow a storm, it's worth a proper inspection before you spend money patching individual slates. Chris Ayre and the team at Ayre Roofing Contractors have been re-roofing homes across Exeter and the surrounding villages since 2009, with a 5-year guarantee on new roofing work — get in touch through ayreroofing.co.uk for a survey.