The Science Behind Accoya Technology

The production process of Accoya does not diminish the innate strength of the original wood. In fact, it slightly enhances its hardness while maintaining its bending strength without compromise. No other modification process matches the performance benefits and the retained physical properties achieved by Accoya.



This process involves the alteration of the wood’s cellular structure, resulting in improved technical characteristics and significantly heightened strength and durability. Natural wood contains “free hydroxyl groups” that interact with and release moisture as weather conditions change.


Consequently, untreated wood is prone to expansion and contraction, especially when utilized outdoors for purposes like siding, window frames, and door frames. The fluctuation in wood’s dimensions often leads to cracking and decay, thereby affecting its overall lifespan.


This inherent property makes regular wood vulnerable to expansion and contraction, especially when utilized outdoors for applications like siding, window frames, and door frames.


Through the acetylation process, hydrogen, oxygen, and carbon chemicals, known as acetyl groups, are formed within the wood. This alteration modifies the structure of the existing free hydroxyl groups (hydrogen and oxygen). Each of these chemicals occurs naturally in all types of wood, with acetyl being produced independently from substances like acetic acid, akin to vinegar. The process is environmentally friendly, utilizing only substances naturally present in wood for the acetylation process to take effect.



By working with Accoya distributors and Accoya coating partners we offer Accoya products factory coated as an Approved Manufacturer. 

Accoya brings unprecedented reliability for timber; it is checked and trusted not to visibly swell, shrink or distort, with minimal movement. Highly durable, it withstands the test of any climate. And what’s more, it stays that way – a 50 year above ground, and 25 year below ground and freshwater warranty are testament to the fact that you can expect to enjoy your Accoya wood for many decades to come. There are no disadvantages to choosing Accoya

Accoya is a highly proven product with testing from many different perspectives, on a worldwide basis. Many tests have been conducted in real life conditions, over many years.

Accoya is so reliable that for many years it has been, and continues to be used by scientists as the benchmark against which other treatments and modified timbers are measured.


Finish sums up many of the reasons architects and manufacturers love working with Accoya – coatings look brilliant and last longer, and its easy and hassle free care save time and money in the long-term. It also offers huge design freedom, with the ability to create a multitude of textural finishes such as planed, sawn and structured / brushed, plus bespoke size and finish options for endless creativity

Finish with the ultimate consistency and quality.

A number of coatings, colours and textures have been applied extensively on Accoya products for over 10 years. The real world performance over this time has matched up to the high expectations built up through extensive testing programs to give you the finish that is required.


Accoya is the truly sustainable choice that helps you meet global challenges like climate change. From source to production and through to end of life, sustainability shines through. Accredited by the FSC® and Cradle to Cradle Gold certified®, it is the only construction material in the world to achieve C2C Platinum certification™ for Material Health. With a low carbon footprint, you can help combat carbon emissions for a healthier world. It’s also non toxic, so safe for people and pets as well as the planet

Accoya’s outstanding sustainability credentials start with the sourcing of the raw material. Accoya only uses timber from FSC® certified forests, that have to prove they are managed in an environmentally appropriate, socially beneficial and economically viable manner.

These forests are a natural, renewable solution for global environmental problems such as climate change, ecosystem destruction and landscape deterioration caused by increasing consumption.


Surface Finishes

Accoya can be coated with a range of surface finishes such as; planed, sawn and structured depending on the coating system chosen. For more information please see our Surface Finishes page. 

Coating and Treatments

If left uncoated, Accoya will naturally weather. We offer a range of coating systems for Accoya in order to meet a range of design requirements. Due to the stability of Accoya it is well suited to opaque and translucent coatings, wood stains and pre-weathered coating systems.