The greatest wood industry innovation of the 21st century. Through a molecular-level chemical modification (acetylation with acetic anhydride), fast-growing plantation softwood is transformed into an inert, hydrophobic material. It achieves Teak-level durability with rot resistance guarantees exceeding 50 years.
Wood chemistry. Hydroxyl groups (OH) bind water causing wood to swell and rot. The acetylation reaction alters this chemical signature, making the material unrecognisable (and indigestible) to attacking organisms.
For millennia, getting durable outdoor timber meant cutting slow-growing tropical species, destroying primary forests, or impregnating pine with toxic copper compounds. Accoya solves the paradox: it chemically transforms fast-growing plantation pine into the most durable and stable wood on the planet, without using any poison.
Raw Radiata Pine boards enter large autoclaves saturated with acetic anhydride under pressure and heat. Free hydroxyl groups (OH), those that bind moisture causing swelling, are permanently replaced by acetyl groups (Ac), which are larger and fill the cell wall space preventing water molecules from penetrating. The wood becomes structurally hydrophobic from core to surface.
Accoya, unable to absorb water, reduces its dimensional movement by 80%. An installed board will stay perfectly flat for decades. Applied paints last three to four times longer than on conventional wood, because the surface does not work and does not tear the paint film.
European and international references applicable.
CRITICAL HARDWARE: the acetylation process leaves a slight residual acetic acid inside the wood. This triggers strong galvanic corrosion on standard or galvanised steel. It is mandatory to use exclusively A2 or A4 stainless steel fixings (AISI 304/316). GREYING: if left bare without UV varnishes, it will naturally assume a silver-grey patina like Teak.
Pool deck or jetty planking. Zero splinters, no board twisting, comfortable underfoot.
PRC.17 · Open the processHigh-performance windows where dimensional stability is crucial to maintain airtight frames year-round.
PRC.27 · Open the processOpen-joint architectural cladding. The 50-year guarantee avoids maintenance at height.
PRC.02 · Open the processStructural posts or retaining walls in direct contact with wet soil or freshwater immersion for decades.
PRC.47 · Open the processThe difference between 8% and 1.5% movement is the difference between a deck whose boards lift and twist in autumn, and one that stays flat as ceramic flooring for its entire service life.
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