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Accoya, the synonym for
Sustainable High-Performance Wood

Ideal for decking, cladding, windows & doors, structures, outdoor furniture and more applications

Accoya® wood is one thoroughly modified wood with high-performance. Created from sustainably-sourced natural wood, Accoya® undergoes a proprietary, non-toxic acetylation process that permanently modifies the wood to the core.

Thus an environmentally friendly solid wood is available with durability, dimensional stability and beauty that matches or exceeds even the best tropical hardwood.

Accoya® wood is sourced from sustainable sources, with FSC® certification and other class leading environmental credentials such as Cradle to Cradle™ Gold certification by the highly prestigious McDonough Braungart Design Chemistry (MBDC) organization.

Diamond Wood China Limited, a licensed distributor of Accoya® wood, is authorized to distribute Accoya ® wood in China and all countries and areas in south east Asia. To meet the growing market demand for Accoya ® wood, Diamond Wood China Limited, is licensed by Accsys (the trading name of Titan Wood Limited), the owner of the Accoya® brand and associated intellectual property, to construct an Accoya® factory in China.

Features & Benefits

Higher reliability, is always shown as the final result of the extensive laboratory and field testing on acetylated wood by leading institutes around the world (including in New Zealand, USA, UK, Sweden, Malaysia, Indonesia, the Netherlands and Japan). Accoya® wood has been thoroughly tested for dimensional stability, durability, paint retention and in-ground conditions to ensure optimal performance. Indeed, it 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 modifications are measured.

Key Features

Dimensionally Stable

  • Swelling and shrinkage reduced by 75% or more
  • Doors and windows open effortlessly year round
  • Reduced maintenance costs

Outstanding Durability

  • Lasting 50 years above ground, 25 years in ground/freshwater
  • Class 1 durability, surpassing even teak
  • Virtually rot proof
  • 70 years minimum service life stated by TRADA

Perfect for Coating

  • Improved stability means coatings last up to two times longer
  • Easier to coat, less preparation and sanding required

Features & Benefits

Naturally Insulating

  • Improved insulation compared to commonly used hardwood and softwood species
  • Ideal for energy-conservation applications

Excellent Machinability

  • Easy to machine and process
  • No requirement to special tools

Insect Barrier

  • Indigestible to a wide range of insects, including termites
  • Greatly reduced vulnerability

Consistent Quality Throughout

  • Consistent, measurable & cross-section modification quality from surface to core
  • No need to apply chemical preservatives when cut or planed

Naturally Beautiful Wood

  • Process does not compromise the wood’s natural beauty

From sustainable sources

  • From FSC, PEFC and other regionally certified woods
  • Naturally renewable

Retained Strength & Hardness

  • The process does not compromise the wood’s strength
  • Increased hardness
  • High strength to weight ratio makes it suitable for challenging applications

Non-toxic & Recyclable

  • Protects the environment from the harmful effects of common treatments
  • Able to be safely reused, recycled and incinerated

Barefoot Friendly

  • Ideal for all decking situations in extreme temperatures
  • Low thermal gain
  • Much less splinters than other wood species when used for decking


Outstanding Durability

Accoya is already inspiring architects, designersand individuals around the world with its outstanding qualities and the possibilities it offers for using wood in exterior applications.

Class 1 Durability

Cellulose is a major structural ingredient of wood, but it is also a major food source for several different insects and decay fungi and makes a great shelter for others, too. Rot causes wood to degrade – particularly when it is used outdoors and exposed to moisture – limiting its service life.

Thanks to the acetylation technology pioneered by Accsys Technologies, Accoya wood offers you an environmentally compatible, durable wood that can be utilized with confidence in outdoor applications and will last for many years.

Simply the Best

‘Class 1’ is simply the top leading level of durability possible in wood. Though there are some naturally durable wood species, it is known that their natural durability is variable with inconsistency.

On the other hand, Accoya wood’s durability is consistent. The properties test of every batch via standard scientific measurements after modification, enable its durability to at least match and even exceed the performance of nature’s most durable species, including teak.

Additionally, Accoya is made using fast growing, sustainably forested radiata pine, while other durable woods tend to be slower growing species. So old growth forests are not threatened or depleted to create Accoya.

Longer Life

Accoya wood’s durability makes it very long lasting, at least:

  • 50 years above ground
  • 25 years in-ground or freshwater contact

The indigestion to microorganisms and insects makes Accoya wood more durable to wood-destroying fungi and virtually rot-proof.

Outstanding Durability

Insect Barrier

Where Durability Counts…

Heavy Traffic Road Bridge: “Several independent European research institutes tested Accoya’s suitability for this project. After rigorous testing, we found that its dimensional stability and incredible durability put it head and shoulders above other species and showed that it is suitable for laminating in large sections measuring 1080 x 1400 mm. Accoya is non-toxic and made from sustainably grown timber and these things were also considerations,” Sieds Hoitinga, Project Manager, Province of Friesland, the Netherlands.

Canal Lining: Certain environments are particularly punishing and few are harsher than canal banks where wood is used to hold back the earth, exposing it to water, microbe-rich soil and – most obviously at the waterline – air. Accoya offers unparalleled performance in this application, exceeding tropical hardwood.

Decking: Applications like decking, where the wood is frequently wet and close to or in contact with the ground, demand a durable wood that is an effective barrier to mould and insect. Acetylation has significantly improved wood performance against brown rot, white rot and soft rot. Accoya wood has also proven to be an effective barrier to wood destroying insect damage in multiple field tests and laboratory trails undertaken in many locations all over the world. This includes tests with multiple species of termites.


Here we’d like to share with you more about Accoya® wood’s outstanding dimensional stability and why this is an important factor when using wood in external applications.

Dimensional Stability

Temperature and humidity are critical factors for many materials in outdoor applications.

Generally wood swells in damp or wet conditions and shrinks in dry, hot conditions, with the unwelcomed results: structures may become unstable; windows and doors may jam or let in drafts; wood may warp or split, leading to insect degradation and more frequent maintenance cycles.

Accoya wood’s superior dimensional stability (resistance to swelling and shrinkage) matches or exceeds all the top leading species in the world, including Teak, Sapele, Iroko and Western Red Cedar.

Outstanding Dimensional Stability

With minimal swell and shrinkage, Accoya wood offers outstanding dimensional stability in both radial and tangential directions (thickness and width) and may be confidently utilized in applications where it will encounter varying moisture conditions – even in freshwater immersion.

Tests have shown the reduction in swelling caused by moisture is improved by 75% or more. From oven dry to water saturated conditions, the swelling and shrinkage of acetylated wood is only minimal and, in fact, better than tropical hardwoods.

Advantages of Dimensional Stability

  • Better fitting windows and doors in all weathers
  • Less frequent coatings maintenance
  • Decreased maintenance cycles
  • Reduced swelling and risk of jamming in humid conditions
  • Cladding that does not cup
  • Floors and decks that stay level

Extreme Conditions

Accoya wood has been tested over prolonged periods in different types of weathering conditions – above ground, below ground and in freshwater – and has been proven to withstand even the toughest and most challenging of environments. Even after a prolonged period of immersion, Accoya window frames keep operating smoothly, without jamming.


Accoya® wood truly is a leading edge material that treads softly on the earth.

If you need use wood in outdoor applications and are considering more sustainability, lower carbon footprint and more energy efficiency, Accoya wood may well be the answer you’ve been looking for.

Higher LEED and BREEAM Scores with Accoya

LEED and BREEAM are clearly the most rigorous and internationally recognized certification systems in the green building industry. Both are based on various building related environmental indicators including sustainable energy, -water and -material utilization.

Better BREEAM Scores

BREEAM is the most important sustainable building system in North-western Europe. Because of the low environmental impact based on Life-cycle assessment (LCA), the low maintenance, the innovative character and the sustainable sourcing (always FSC or PEFC), support the application of Accoya to yield a higher BREEAM International score (MAN 5, MAT 1, MAT 3, Inn 1).

More Credits for Accoya in Latest LEED Version

Even if Accoya was already rewarded in the previous (v2009) LEED BD+C system through the sustainable wood sourcing (credit MR 7), in the latest version v4, because of the transparent environmental reporting (LCA, EPD, carbon footprint), the benign environmental profile including C2C Gold certification, and even the light colour (heat island reduction), application of Accoya contributes to even more credits.

Sustainable Accoya® Home Receives Platinum LEED Certification

One of the USA’s most sustainable family homes, constructed with the extensive use of Accoya wood, has been awarded platinum level LEED certification – the highest recognition available from the US Green Building Council.


If the frequently maintain coatings on wood is bothering you, not just in terms of time and cost but also in terms of the associated environmental impact, then you will love the coatings performance advantages associated with Accoya® wood.

Superior Coating Performance

Accoya® wood’s outstanding dimensional stability primarily contributes to its superior coatings performance. Thus any major coating systems can be applied on Accoya® with significantly improved performance.

Dimensional Stability & Coatings

Less swelling and shrinkage (by 70%-80%) of Accoya wood, better coating adherence to its more stable surface. Dimensionally stable wood improves coatings life as paints and other film-forming coatings are not subjected to severe stretch and shrink cycles. The final result is decreased maintenance frequency, causing to:

  • Less time to maintain the wood
  • Less money spent on coatings
  • Less coating used during the overall service life of the wood
  • Less impact on the environment

Accoya works well with all known coatings systems. Extensive testing with positive results has been performed with opaque hybrid, opaque acrylic and transparent alkyd emulsions coating systems.


Why Accoya® wood is such an exciting and groundbreaking product – one that will enable you to apply wood with absolute confidence, even in external applications.

Consistent Quality & Ease of Use

As a natural material, each piece of wood is unique with frustration and uncertainty when looking for guaranteed performance quality. However, Accoya wood offer you the guaranteed features, such as consistent quality, durability and dimensional stability.

Wood acetylation is a process that has been studied by scientists around the world for more than eighty years. The Accoya wood manufacturing process combines this work with years of proprietary research and investment to deliver consistent results on a commercial scale. Especially, the effectiveness assessment of the acetylation process is measured after Accoya wood has been produced, with an array of sophisticated and proven analytical techniques.

Outstanding Durability

Each batch is analyzed and Accoya wood always meets the requirements of Durability Class 1 for Use Classes 1-4 in accordance with EN 350-1 & EN 335-1.

Consistent Quality Throughout

As Accoya wood is modified all the way through, rather than just at the surface, when it is cut, planed or jointed there are no exposed unprotected surfaces in any dimension. This completely removes the need to apply additional chemical preservatives to the unmodified or envelope treated woods.

Excellent Machinability & Ease of Fixing

Easy to machine and process manually, Accoya wood is creating almost challenges for product manufacturers and end users. Accoya wood can be fixed in the same way as other commonly used softwood species. As with one of the most durable woods, Accoya contains a small amount of acid. It is therefore strongly recommended that corrosion resistant fixings, such as high quality stainless steel, are used.

Retained Strength & Hardness

The manufacturing process does not compromise the wood’s strength. In fact, the hardness of the wood is increased and because Accoya wood has a high strength to weight ratio, it is suitable for challenging applications – even heavy traffic road bridges.

Naturally Beautiful Wood

Last but not least, Accoya wood is naturally beautiful. It is comparable in colour to the original source species, so that you can achieve a natural look in your projects if you wish or it may be easily coated in a wide range of colour finishes. It’s up to you!.


Building Bridges

Accoya has been applied to create a unique “floating” bridge in the Dutch city of Bergen op Zoom.

Ro Koster and Ad Kil, of Bergen op Zoom-based RO&AD Architects, who also mastered the famous and award winning Moses Bridge in Halsteren, designed the 80m floating pedestrian bridge to realize the access to the 18th century fort’s entrance. Its snake-like path mimics the journey and motion of the boats which originally travelled there.

Windows & Doors

The improved thermal insulation compared to commonly used wood species and more durability and dimensional stability than the best tropical hardwoods, enable Accoya wood as one brilliant material for windows and doors. Based on the third party testing of Accoya, its expected service life is now independently reported as extending to 70 years when used for window joinery in the UK and Europe as well as being Carbon Negative over its life cycle. Coatings last longer and it is perfect for transparent, translucent or opaque coatings… whatever captures your imagination.

Finely Clad

Any cladding, siding and façades with the consideration on aesthetics, stability, durability and less frequent maintenance, Accoya wood will jump to mind. Here it is used to clad a contemporary extension using an inclined open boarding system, finished with an environmentally friendly dark or light stain.

On Deck

The beauty, strength and all-weather performance are crucial for decking, jetties and pontoons. A dimensionally stable material that will stay flat and has very minimal bow, cup, warp and split and will not be affected by fungi or rot is ideal. It is also important that the wood is non-toxic and therefore safe for people and animals. Accoya wood meets these requirements.

In the Shade

Accoya wood is an excellent choice for shutters, louvres and solar shading.

Acetylation Process

Step 1

It is the acetylated wood technology, that creates Accoya wood Over 80 years ago, the scientists around the world has studied the process.

The proven superior performance, delivered by the wood improvement method, has long been used as the “gold standard” against which other methods are measured.

Step 2

The chemical structure of any material will determine its physical properties. There is an abundance of chemical groups called “free hydroxyls” in wood, which absorb and release water according to changes in the climatic conditions to which the wood is exposed. This is the key reason why wood swells and shrinks.

It is also believed that enzymes’ digestion of wood initiates at the free hydroxyl sites – which is one of the principal reasons why wood is prone to decay.

Step 3

Acetylation effectively transfers 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).

The transformation from the free hydroxyl group to an acetyl group, greatly reduces the water absorption ability of the wood, and render the wood more dimensionally stable and extremely durable.

Step 4

Acetyl groups naturally exist in all wood species. This means that the acetylation process adds nothing into the wood, but alter the wood’s chemical structure to create an end product that is dramatically superior to its source species.

Accoya® wood, the end product, has no toxins in itself, moreover it releases none toxins to the environment.

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, to improve durability to a degree, but without dimensional stability.


Diamond Wood China Ltd.

Shanghai Headquarters:

Room 540,  5F, The Hub Tower 3, No.888 Shen Chang Road, Shanghai, PRC. 201100

+86 21 2351 6220

Sales Manager in South East Asia

Mr. Olivier Roy
Tel: + 84 908 02 43 20
Email: olivier.roy@diamondwoodchina.com

Sales Manager in China

Mr. Stephen Jie
Tel: +86 138 1003 0460
Email: stephen.jie@diamondwoodchina.com

Sales Manager in Thailand

Mr. Sakda Kunaphan
Tel: +66 929 263 526
Email: sakda.kunaphan@diamondwoodchina.com