The Penrhyn Heather Blue slate, also known as Bangor Blue, is one of the most widely used slates. The Penrhyn quarry has been producing roofing slate since the 13th century, and is regarded as being the best in the world. Welsh slate is extracted from some of the world’s finest deposits, formed up to 590 million years ago. Of that extracted only less than 10% is used. They are renowned for the consistency of their color and texture.
After 100 years of use, the quality of Welsh slate Australia is such that typically 50% of it is re-used. There is no other roofing material which has demonstrated this exceptional durability.
Penrhyn Welsh slate has been exported to Australia since the very early days of Australia’s settlement. In the early days of the colony, roofs were generally made of bark and sometimes timber shingles.
However these were not good waterproofing materials. Slate was initially used as ballast on trading vessels being sent to Australia to collect timber. When the slate arrived into Australia it was then used as a roofing material on many civic buildings and churches. The first records of Welsh Penrhyn slate being used was in the Rocks, Sydney in 1820.
Welsh Slate Properties
|Sunlight unfading||Unaffected by UV light|
|Heat||Unaffected by normal heating, freezing and thermal cycling|
|Chemical resistance||Unaffected by atmospheric pollution, sea air and sea spray|
|Biological resistance||Unaffected by vegetable growth, rot or insect attack|
|Compatibility||Compatible with all building materials|
|Fire resistance||Slate is non combustible and does not support combustion. AA fire rating|
|Thermal expansion||8.5 - 11x10-6 mm per degrees celsius|
|Thermal conductivity||Approx. 2.0 W/mk|