Extensive laboratory and field testing by leading institutes around the world (including in New Zealand, USA, UK, Sweden, Malaysia, Indonesia, Russia, the Netherlands and Japan) has shown the performance of acetylated wood to be extremely reliable. Accoya® wood has been thoroughly tested for dimensional stability, durability, UV resistance, 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.
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 used with confidence in outdoor applications and will last for many, many years.
As ‘Class 1’ suggests, this is simply the best level of durability possible in wood. Whilst some wood species are naturally durable, natural durability is known to be a variable and inconsistent property.
Accoya wood, on the other hand, is consistently durable. The properties of every batch are analysed by standard scientific measurements after modification, enabling its durability to at least match and even exceed the performance of nature’s most durable species, including teak.
Additionally, durable woods tend to be slower growing species, whereas Accoya is made using fast growing, sustainably forested radiata pine, so old growth forests are not threatened or depleted to create Accoya.
Accoya wood’s durability makes it very long lasting, at least:
- 50 years above ground
- 25 years in-ground or freshwater contact
Accoya wood forms an effective barrier to mould and insect attack; it is indigestible to microorganisms and insects and therefore more durable to wood-destroying fungi and virtually rot-proof.
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 also has superior UV resistance, 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, replacing 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 mould and insect barrier. Acetylation has been shown to significantly improve 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 in the world. This includes tests with multiple species of termites.
Dimensional stability can be defined as the degree to which a material maintains its original dimensions when subjected to environmental changes. With many materials temperature and humidity are critical factors.
In the case of wood, swelling in damp or wet conditions and shrinkage in dry, hot conditions can have unwelcome implications: windows and doors may jam or let in drafts; wood may warp or split, leading to insect degradation and more frequent maintenance cycles; structures may become unstable.
Accoya wood’s superior dimensional stability (resistance to swelling and shrinkage) matches or exceeds all the best species in the world, including Teak, Sapele, Iroko and Western Red Cedar.
Accoya wood offers outstanding dimensional stability in both radial and tangential directions (thickness and width) meaning that it has minimal swell and shrinkage and may be confidently used in applications where it will encounter varying moisture conditions - even in freshwater immersion.
Tests have shown a reduction in swelling caused by moisture uptake of 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.
- Reduced swelling and risk of jamming in humid conditions
- Better fitting windows and doors in all weathers
- Less frequent coatings maintenance
- Cladding that does not cup
- Floors and decks that stay level
- Decreased maintenance cycles
Accoya wood was the only wood that did not cup in this TRADA (Timber Research & Development Association) trial on wood cladding.
Accoya wood has been tested over prolonged periods in all 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 operate smoothly, without jamming.
Accoya wood has been used for replacement windows in two lighthouse restoration projects.
"The new windows have made a vast improvement to the property visually and in terms of energy and heat retention and have made a significant reduction in noise from the wind in such an exposed location."
David Shaw, owner, Belle Tout Lighthouse
By significantly enhancing the durability and dimensional stability of fast-growing and abundantly available certified wood species, Accoya wood provides compelling environmental advantages over slow-growing hardwoods, woods treated with toxic chemicals and non-renewable carbon intensive materials such as plastics, metals and concrete:
Green Life Smart Life™ is a green building showcase home on the Rhode Island coast of the USA. The home is designed to demonstrate how families can make lifestyle choices that are sustainable and meet their needs without compromising the environment's needs. Accoya was the ideal choice for the front and rear decks and contributed to the project’s LEED-H points in the category of Materials & Resources. The home achieved an official rating by the US Green Building Council as a GOLD certified LEED® for Home Project and was the first LEED-H Gold Home in Rhode Island.
In the water
In the Netherlands Accoya wood is proving to be a high performance, environmentally positive alternative to pressure treated wood and tropical hardwoods in civil works, including particularly demanding applications such as canal lining.
Early canal lining trials gave excellent results, with acetylated wood showing no discernible degradation at all, even after 10 years in the water.
On the water
The first boats to be made entirely of Accoya wood have been launched in the Netherlands.
Based on a design dating from 1958, the boats were previously built from tropical hardwood but the boat builder, Koo-Boten, is committed to building only sustainable and environmentally friendly boats and Accoya was therefore the obvious choice.
Open to the elements
In the 2010 Solar Decathlon, an international competition that challenges universities to design and build a self-sustaining, energy-efficient solar house, the University of Florida’s team, Project RE:FOCUS, sought sustainable, high performance materials for its innovative design. Accoya wood was chosen for adjustable exterior shading.
“Accoya wood really fell in line with our sustainable goals for the house.” Paige Mainor, Project RE:FOCUS design contributor
Accoya® wood’s superior coatings performance is primarily due to its outstanding dimensional and UV stability. This effectively means that major coating systems can be used on Accoya® with significantly improved performance.
With Accoya wood, swelling and shrinkage is reduced by 70-80% and the resultant more stable surface allows coatings to adhere better. Dimensionally stable wood improves coatings life as paints and other film-forming coatings are not subjected to severe stretch and shrink cycles. In the end, the result is decreased maintenance frequency, resulting in:
- Less time spent maintaining the wood
- Less money spent on coatings
- Less coating used overall during the service life of the wood
- Less impact on the environment
Accoya wood has superior resistance to UV degradation, with extensive tests demonstrating that the natural beauty of the wood lasts longer in even the severest exposed conditions. UV resistance of wood improves the life of any coating by providing a sound coating substrate. It also allows a wider range of feasible colour options. For example, very light pastel coloured stains and clear coatings can be safely used because Accoya will not darken quickly and ruin the effect as most other woods do.
Accoya works well with all known coatings systems. Extensive testing has been performed with opaque hybrid, opaque acrylic and transparent alkyd emulsions coating systems.
Return to Fife
This architect-owned private house near Glenrothes, Fife, used approximately 30m2 Accoya wood profiled facade cladding and was completed in July 2006. The cladding was factory coated with translucent Sikkens Natural Balance coating system giving a smooth contemporary finish. After 6 years, the cladding shows no sign of decay, despite the property’s far northern latitude and 10km proximity to the sea. The coating continues to perform well, with no blistering or cracks. The slightly dirty appearance of the cladding is due to tree sap from surrounding trees but the owner reports that this is simply and easily washed off.
Twenty one energy efficient homes featuring windows and doors clad in Accoya wood were completed for Eildon Housing Association at Tweedbank in the Scottish Borders area in 2007. Eildon chose Accoya wood after analysis of the product's aesthetic and durable qualities. More than 11,000 linear metres was used, finished with a Sikkens coating by Environmental Coatings. After more than 3 years in situ, there are no signs of rot, decay cracking or blistering as is common in this challenging environment and colour retention is excellent.
“We are delighted with the performance of Accoya, which reflects our commitment to increased sustainability levels and innovative technology.” Laurence Cox, Eildon.
In the shade
Accoya wood was used as part of a bespoke solar shading system by Levolux in this Scottish Widows office in Edinburgh, Scotland. 1,060 wood fins were used in combination with glass fins and Matrix XL Brise Soleil.
Levolux was able to offer a 10 year warranty for the finish and a 60 year life expectancy and over 2 years later the fins look and perform as new, despite the challenges encountered in this type of thin profile, fully exposed application.
Wood is a natural material and each piece is unique. This is partly what makes it so aesthetically pleasing and yet it can be a source of frustration and uncertainty when looking for guaranteed performance quality. However, with Accoya wood you can be sure of its 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 production process combines this work with years of proprietary research and investment to deliver consistent results on a commercial scale. Unusually, the effectiveness of the process used to manufacture Accoya wood is measured after the wood has been produced, using an array of sophisticated and proven analytical techniques.
Each batch is analysed 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.
Because 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 as is necessary with unmodified or envelope treated woods.
Accoya wood is easy to machine and process manually, creating no challenges for product manufacturers and end users. Accoya wood can be fixed in the same way as other commonly used softwood species. As with 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.
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.
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. The choice is yours.
Accoya wood inspired OAK architects to design two wooden heavy traffic road bridges for the city of Sneek in the Netherlands. Accoya was finger jointed and laminated into large sections measuring 1.08 x 1.4 metres to create these innovative structures, the first of their kind in the world.
Accoya wood is a brilliant material for windows and doors as it offers improved thermal insulation in comparison with commonly used wood species and is more durable and dimensionally stable than the best tropical hardwoods. Coatings last longer and it is perfect for transparent, translucent or opaque coatings ... whatever captures your imagination.
Accoya wood is suitable for cladding, siding and façades where aesthetics, stability, durability and less frequent maintenance are considerations. Here it is used to clad a contemporary extension using an inclined open boarding system, finished with an environmentally friendly dark stain. This is only possible using a wood as stable and UV resistant as Accoya.
In specifying decking, jetties and pontoons, beauty, strength and all-weather performance are important. 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 desirable. It is also important that the wood is non-toxic and therefore safe for people and animals. Accoya wood meets these requirements.
Accoya wood is an excellent choice for shutters, louvres and solar shading. At Scottish Widows’ Exchange Place development, eye-catching bespoke solar shading and ventilation louvres were incorporated to prevent excessive heat gain. The system included 1,060 Accoya wood fins. The solar shading has a life expectancy of 60 years and the finish applied carries a 10 year warranty.