ThermoWood Ash Hardwood Decking

Other board widths available: 40mm, 90mm, 115mm, 130mm, 150mm
Board Lengths: 1.0m upto 3.6m

Thickness: 21mm

Please contact us for specific sizes.

ThermoWood Ash Hardwood is an essential material used for high end joinery due to its amazing durability and strength. ThermoWood Ash is a hardwood with a high number of growth rings and features a vibrant grain structure making it look very appealing. A multi-purpose, aesthetic and durable material for use externally and internally in a beautiful brown colour. It is good for outdoor areas where an elegant look is desired for the elevations on your property.

The Ash timber used in the ThermoWood production process is sourced from North America

because of the higher quality that the cold and dryer climate provides, instead of European Ash which is of a lower quality.

Why Choose ThermoWood Ash Hardwood Decking for the UK Climate?

The ThermoWood process removes the natural resins, sugars, and impurities present in all timbers, and the sugars caramelise which changes the colour of the timber to a dark brown colour. Natural timbers are prone to expanding, contracting and distorting across their width, however, this process minimises that problem. This is very important given the high and variable moisture levels we experience in the UK.


FSC Certified: TT-COC -002360 FSC 100%

ThermoWood Ash Hardwood benefits to you the customer.

  • 30 + years Durability (Class 1)

  • Exceptional Stability

  • Only 7% Moisture Content (Natural Timbers are around 18%)

  • Class B Fire Rated (USA Data for American Ash)

  • 100% Environmentally Friendly.

  • No additives to aid stability.

  • No Amazonian timbers used.

  • No ThermoWood timber goes into Landfill sites.

  • Waste can be used in Household Wood burners.




High Stability


High Quality




Easy Installation


Highly Durable 

What is ThermoWood?

ThermoWood is a thermal modification procedure that preserves wood in its most natural and flawless state for a life-long journey. The “ThermoWood method” involves a carefully computer controlled heat and steam process up to 210 degrees C.

Besides the preservation, the ThermoWood process also causes certain chemical changes in wood. Not only does the colour darken but the stability, decay resistance and insulation properties are largely increased after the process is complete.

The ThermoWood method, brand, and logo can only by the used by members of the International ThermoWood Association.


"CLICK TO LEARN MORE ON WHY THERMOWOOD IS PERFECT FOR THE UK CLIMATE and steal all our helpful hints on installation"

Get In Touch!

We’d love to hear from you; whether you have a question, have a query or a project in mind, we’d love to know! Please use our contact form above or if you would like to talk to us, call on: 0118 373 2212