Accoya door FAQs

• What benefits does Accoya acetylated wood have over unmodified wood?

  Virtually all wood preserving treatments today work by impregnating toxic chemicals (such as arsenic, oils, ammonia or metal compounds) into the cell walls of the wood. This works to fill the voids within the wood but this doesn’t change the underlying chemistry. The toxicity of such products also have negative environmental implications during the serviceable life of the wood as well as during its disposal.

  As an alternative, Accoya alters the wood’s structure to the core, creating an inhospitable environment and helping to control unwanted organisms, such as bacteria, viruses and fungi. The main alternative non-toxic preservative treatment to Accoya’s acetylation is “thermal modification”, a process which works by breaking down the edible components of the wood. However, the process both discolours and weakens the wood, rendering it unsuitable for many uses.

  The Accoya production process does not weaken the original wood – in fact, its hardness is slightly improved and its bending strength uncompromised. Indeed, no modification process exists which offers the performance benefits and retained physical properties of Accoya.

• Do I need to coat Accoya wood?

  From a technical performance perspective, in respect of attributes such as durability and dimensional stability, there is no need to finish Accoya wood for cladding and decking applications. However, joinery applications are more complex so it is recommended that you seek expert advice before using Accoya for uncoated windows and doors.

  Like any natural wood species, Accoya wood is susceptible to weathering in outdoor circumstances. All materials exposed to exterior conditions are degraded by a series of chemical, biological and physical processes. The surface of any wood will be blemished by a combination of UV, moulds, algae, mildew, yeasts and pollution.  Accoya is no exception and the initial light colour of uncoated Accoya may causes early moulds and blemishes to stand out more than on other wood types, prior to it weathering further to grey.

• What makes Accoya so special?

  Wood is an amazing material with many possibilities and practical applications. One of the major drawbacks of wood though, especially softwood, is how it interacts with water. Moisture causes the wood to swell and shrink, and accelerates damage and decay.

  So, what is acetylation?

  Wood naturally contains some acetyls, but also a lot of ‘free hydroxyls’ – these are what water binds to, causing all those problems. In our reactors, our process uses acetic anhydride – essentially very strong vinegar – to boost the acetyl content of the wood, replacing those hydroxyls…meaning water is no longer an issue.

  This means we’re not adding anything to the wood that wasn’t already there – no toxic elements that could later leach out - we are really enhancing the natural qualities of the wood.

  Even the by-product of our process is part of the circular economy: acetic acid is valued in its own right, used in other products, processes or even turned back into acetic anhydride – offering a potentially ‘closed loop’ cycle for our chemistry.

  We constantly refine and improve our processes to improve quality and efficiency, and research the effects with different wood species.

  Watch our video here.

• What is Accoya wood made from?

  Accoya wood is made from radiata pine trees. These are sourced and taken to our production facilities in the Netherlands where they undergo a modification process, more specifically known as Acetylation. This process turns the radiata pine wood into the worlds most stable wood, Accoya.

  More information about the Acetylation process can be found here.