Brimstone by Vastern Timber

Officially unveiled at Ecobuild 2016, Brimstone is the first commercially available thermally modified British timber. Sourced exclusively from English and Welsh woodlands, the Brimstone range is designed for cladding, decking, external joinery and furniture, and includes thermally modified British hardwoods including ash, sycamore and poplar.

The thermal modification process reconfigures the wood to deliver a material of high dimensional stability, durability and aesthetic uniformity that also increases resistance to fungal decay. The Brimstone range represents new levels of sustainability for specifiers interested in modified timber products, as the process does not rely on impregnating the timber with chemicals.

Brimstone ash weathered.

Also, by using home-grown timber the development of Brimstone creates value for the UK’s native woodlands. The chemical-free process and the use of home-grown timber are the two key features that make the Brimstone range a worthy candidate for our Featured Product of the Month.

The product and benefits

A proven technology, thermally modified timber is 60 – 80% more stable than non-modified timbers, meaning significantly less expansion and contraction when faced with changes in ambient temperature and humidity, making thermally modified timber a superior solution for a range of exterior uses.

The thermal modification process also results in a product that is naturally durable to its core. Similar imported thermally modified hardwood products reach the equivalent of Class 2 (EM350), giving a minimum service life of 30yrs when used above ground. Brimstone products are currently being tested by the BRE for durability, stability, strength and hardness to provide specific data for the range of British white hardwoods. The ASBP will follow the development of this product range and provide an update on testing when the results are available later this year.

Ash timber.
Ash timber.

Imported thermally modified products are already widely available and growing in popularity as the benefits become more widely recognised. What sets Brimstone apart is that it is produced exclusively from trees grown in English and Welsh woodlands, and from species that are currently underused, thereby supporting our local domestic woodlands and offering clear benefits with regards to miles travelled, carbon impact and wider social value to the UK.

About Vastern Timber

Established in 1904, and with two sawmills in Wiltshire, Vastern Timber is one of the largest British hardwood sawmills in the country, specialising in cutting and manufacturing native grown timbers including English oak, sweet chestnut, ash, sycamore and larch. A family business, Vastern Timber is owned and run by three members of the Barnes family: Peter, Jon and Tom, who represent the third and fourth generations of family working in the company. Cutting and processing its own logs allows Vastern Timber to offer a range of species, grades and specifications that are not widely available from other merchants.

Further information:

For more information on Brimstone modified wood products visit

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