The poor state of Bodmin Jail’s local natural slate roof left its Cornish custodians with a dilemma. Twelve Architects’ redevelopment of grade II listed 18th-century Bodmin Jail included the specification of SSQ Riverstone phyllite slates and Velux glazing panels.

How do you maintain the period character of a structure that was originally fitted with an indigenous slate roof that is now well past its prime and needs replacing?

That was the dilemma faced by the custodians of Cornwall’s Bodmin Jail.

Bodmin Jail roof with Riverstone

They wanted a roofing product that could emulate the aesthetics of the 600x300mm dry-laid Cornish slate that made up the original roof, but that was more readily available.

That led them to consider SSQ’s Riverstone Ultra phyllite – both for its similarity to Cornish indigenous slates Delabole and Trevillet in terms of its strength, colour and geological profile and for its long track record of being approved by Cornwall Council’s Historic Environment and Planning Team

The slates were laid using a 200mm gauge. They were copper nailed twice onto 500x200mm factory-grade treated counter battens, which were fixed to a ply roofing deck using a Permavent Apex Air breather felt.

Bodmin Jail roof with Riverstone

The finished result was a roof that had been seamlessly integrated with the modern design of the renovated buildings’ roof structure in a way that protected the centuries-old building underneath and honoured its historic aesthetics.

If you’d like to find out more about SSQ natural slate, get in touch today. For more information about any of our slates call 020 8961 7725 or send us a message online and we’ll get back to you as quickly as possible.

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