Caithness flagstone technical specifications

Caithness flagstone's striking appearance and exceptional strength makes it highly sought after for public spaces, corporate interiors, building projects and high end residential architecture. 

This high-density sedimentary sandstone is extracted from a 3 m high bed and quarried from 16 principle layers. These layers are split into a total of 49 individual flagstones, ranging in thickness from 20 mm to 160 mm. We carefully select our stone from the layer best suited to the end use.


Caithness Flagstone is from the Old Red Sandstone of Devonian age. It is very fine grained with a dark grey colour which weathers to various colours dependent on the iron content in the area of extraction. When polished, the hewn stone finishes darker and more consistent in colour, giving Caithness Flagstone its signature, striking dark look.

Technical Information

Slip Resistance 69µm Rz (wet) 96µm Rz (dry) BSEN 1936: 2006
Water Absorption 0.2% BSEN 13755:2008
Flexural Strength 35 MPa BSEN 13161: 2008
Frost Resistance 12.7 MPa BSEN 12371: 2001
Compressive Strength 209 MPa BSEN 1926: 2006 | 117 MPa BSEN 772-1: 2000
Abrasion Resistance 22.5mm BSEN 1341: 2013

Quality assurance

We understand the design and build process and are routinely selected as a supplier where Caithness flagstone is specified.

We quarry, cut, finish and deliver all material to specification.