Brimstone is a range of thermally modified British hardwoods manufactured and supplied by Vastern Timber. Brimstone is created by heating the wood to 200°C+ under controlled conditions, a process known as Thermal Modification. This natural, toxin-free method removes moisture, resin and other extractives. The result is a more durable, stable and consistent material that is ideal for external cladding, decking and some joinery applications. Brimstone is available in three versions, Brimstone ash, Brimstone poplar and Brimstone sycamore, all of which are sourced from GIB accredited woodlands in England and Wales. The wood is highly selected to produce a relatively defect free grading of Class 1 (BS1186-3) or J20 (EN942:2007), ideal for clean and contemporary designs.

The thermal modification process transforms non-durable white hardwoods into products with the highest levels of durability when used away from ground contact. Lab based testing of Brimstone by EPH Dresden has indicated Class 1 durability (EN350-2) for all three versions. Testing has also indicated a 50 – 60% improvement in stability after the modification process.