Penrhyn Welsh Slate Roofing

Penrhyn Heather Blue slate, also known as Bangor Blue and Penrhyn® Purple, is produced from a fine-grained slate deposit, laid down over 500 million years ago in the Cambrian period.

Penrhyn Quarry in the heart of Snowdonia is one of the largest slate quarries in the world, and has been in commercial production for over seven centuries. The properties of the Penrhyn® slate allow it to be split into thin sheets but still retain its strength and unparalleled durability.

More Information

  • Check Mark Highest quality materials
  • Check Mark Technical expertise
  • Check Mark Outstanding customer service


Penrhyn Welsh Slate roofing is available in three thickness grades: Capital, County, and Celtic. The thickness of the three specific grades is to suite the range of different roofing project requirements.

The quality of the stone will allow production of roofing slates in excess of 1 metre in length, but the majority of the production is focused on the core production sizes (500 x 300 mm, 400 x 250 mm and 300 x 200 mm) in three thickness grades; Capital (5.5 mm), County (7 mm), and Celtic (9mm). Each grade of slate has a subtly differing character, but all have the intrinsic quality that makes Penrhyn® Slate the envy of the slate world.