Reducing Environmental Impact, Improving Performance.

Accoya® is wood, but not as you know it. It is modified timber in which a process called acetylation, a cutting-edge patented technology, enables it to resist rot, defy the elements and stay strong for decades. Guaranteed for 50 years above ground and 25 years in ground or freshwater, its performance and properties are remarkable. From joinery for the home to bridges submerged in water, Accoya long life wood is a leading material that stands up to every application challenge – decking, wood cladding and more.

The Minnesota State Capital

Saint Paul, USA

Accoya® windows

Features & Benefits

Key features

Perfect for

Accoya® modified timber has properties that match or exceed those of the best tropical hardwoods and treated woods, yet is manufactured using wood from sustainable sources.

Accoya® is the world’s leading high technology long life wood.

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Accoya used for A.P.C Clothing Store

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Stunning curved Accoya wood cladding and shading in the Netherlands

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Accoya modified timber used in Caldding
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Accoya used to imitate the essence of a treehouse

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Accoya high performance wood used in the Fitzroy House

Acetylation Process

Step 1
Accoya high performance wood is based upon acetylated wood technology, a process that has been studied by scientists around the world for more than 80 years.

This method of improving wood has been proven to deliver such superior performance that it has long been used as the “gold standard” against which other methods are measured.

Acetylation Process

Step 2

The physical properties of any material are determined by its chemical structure. Wood contains an abundance of chemical groups called “free hydroxyls”. Free hydroxyl groups absorb and release water according to changes in the climatic conditions to which the wood is exposed.

This is the main reason why wood swells and shrinks. It is also believed that the digestion of wood by enzymes initiates at the free hydroxyl sites – which is one of the principal reasons why wood is prone to decay.

Acetylation Process

Step 3

Acetylation effectively changes the free hydroxyls within the wood into acetyl groups. This is done by reacting the wood with acetic anhydride, which comes from acetic acid (vinegar when in dilute form).

When the free hydroxyl group is transformed to an acetyl group, the ability of the wood to absorb water is greatly reduced, rendering the wood more dimensionally stable and extremely durable.

Acetylation Process

Step 4

Acetyl groups are already naturally present in all wood species. This means that the manufacturing process adds nothing into the wood that does not already occur within it.

The end product, Accoya® wood, does not add toxins to the environment. The effect of altering the wood’s chemical structure, as opposed to merely altering its chemical content, is to create an end product that is dramatically superior to its source species.

Acetylation Process

Step 5

Accoya wood is modified right through the cross section whereas, by contrast, virtually all other treatments merely insert chemicals (such as oils, ammonia or metal compounds) into the wood, improving durability, to a degree, but not dimensional stability.

Where to buy

Distributed in over 50 countries worldwide

Find your nearest Accoya distributor through our ‘Where to buy’ page.

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Windows & doors with certainty

With our 50 year guarantee homeowners can be assured that Accoya windows and doors will help your home reach its full potential.

Take a look at our new Accoya windows and doors site for ideas, and to contact your local UK manufacturer.

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