Welsh Slate Supplier Northern Ireland - Valley Roofing leading supplier of Welsh Slates

Welsh Slates, Penrhyn 'Bangor Blue'

Penrhyn Bangor Blue Slates are regarded as the best quality roofing slates in the world.

They are quarried at the Penrhyn Quarry in Bethesda, North Wales at the edge of Snowdonia National Park, from a slate deposit that was formed in the Cambrian era (600 million years ago).  As such, they are an extremely pure, hard and dense slate.  Penrhyn slates are recognizable from their distinctive heather blue / purple colour, and textured grain.  They are one of the only roofing slates in the world which do not contain any potentially damaging inclusions or iron pyrites. 

Penrhyn Bangor Blue slates cover many of the world’s most prestigious buildings including Buckingham Palace and the British Museum in London.  They are popular on a wide variety of buildings from bespoke architectural homes, to historical buildings (such as Victorian and Georgian period properties), to Churches, Cathedrals, Castles and Museums.

These slates truly do have a global world-wide appeal and are still as popular in many countries around the world (France, Germany, Holland, Belgium, North America, Australia and New Zealand), as they are in the home markets of Ireland and Britain.


Please contact us on 02877741686 or info@valleyroofing.co.uk to get more technical information or pallet quantites.

Bangor Blue slates come in standard sizes of 500x300mm (20 x 12”)- note other sizes are available on request, and in 3 thicknesses:

  • Capital Grade (5.5mm Nominal Thickness)
  • County Grade (7.5mm Nominal Thickness)
  • Celtic Grade   (9.5mm Nominal Thickness)

Penrhyn roofing slates conform to BS 12326-1:2014 (W1, S1, T1), hold BS Kitemark Accreditation, and are generally expected to outlive the life of a building (when fixed in accordance with BS 5534 / S.R. 82:2017).


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