FSC Certified Accoya Lumber: Durable, Stable, and Water-Resistant
Pinus Radiata
Accoya is a high-performance, modified wood made from FSC-certified Radiata Pine. Using a process called acetylation (essentially applying strong vinegar), the wood’s structure is altered to resist water and rot, while staying stable with minimal seasonal movement. Water can’t bond to the wood, preventing decay and swelling.
Ideal for Decks, Docks, and Siding
Accoya is harder and more durable than regular pine, performing like hardwood with twice the strength. Its stability and rot resistance make it perfect for decking, whether face-screwed or clip-installed. For a weathered look, Accoya Color Grey is pre-treated with carbon pigments, offering a consistent grey tone that lasts.
As siding or cladding, Accoya’s lightweight, water-repellent, and dimensionally stable properties allow for wide boards (up to 8″) without warping. Its excellent insulation and hydrophobic qualities make it ideal for rainscreens, Passive House designs, and wildfire-safe (WUI-compliant) assemblies.
Accoya combines durability, stability, and style for versatile outdoor applications.
Joinery made easy
Unlike thermally modified wood, Accoya stays strong and flexible, making it ideal for joinery like windows, doors, and decorative cuts such as mortise-and-tenon or dovetails. It glues easily, but polyurethane glue is recommended for better results due to the wood’s dryness. PVA glue works too, but it needs longer clamping times.
Superior Finishing
Accoya is excellent for painting, staining, or charring (Shou Sugi Ban), thanks to its smooth texture and light color. Its stability means finishes last longer without cracking, peeling, or fading, because the wood doesn’t expand or contract with weather changes. This reduces maintenance and keeps your projects looking fresh.
However yOu Use Accoya, we can make it
Learn More about Acetylated Wood
It’s not treated, it is modified. The process changes the internal structure and augments the chemical components already naturally present in wood.
Accoya Warranties
Acetylated outperforms natural, unmodified woods to such a degree that Accoya has created a warranty for all their materials. 50 years on above-grade applications and 25 years for in-ground and fresh water contact. You can read more and download the Accoya Warranty here.
Accoya Wood Applications
Accoya Wood CHARACTERISTICS
The important thing to remember is that Accoya is wood. Cut it, sand it, finish it, & install it like any wood. Yes, it moves much less and can be used in a wide variety of applications, but use typical best practices for natural wood, and it will treat you well.
| Character | Accoya |
| Bending Strength (MOR) | 1,297,422 lbf/in2 |
| Stiffness (MOE) | 13,144 lbf/in2 |
| Hardness (Janka) | 922 lbf |
| Fire Rating | Class C |
| Weight | 32 lbs/ft3 |
| Radial Shrinkage | .7% |
| Tangential Shrinkage | 1.5% |
Accoya Wood Sizes
We are stocking Accoya lumber in a wide variety of sizes and can mill it to your specific project needs. J. Gibson McIlvain can add any number of cladding profiles or decking profiles for clip fasteners. We can create custom architectural millwork like railing, panels, shutter, doors, etc. We can even glue up laminations and posts if your project demands it. Finally, we will finish and texturize to create your final custom look. The limitation is only your imagination, so let us know how we can help with your project.
Here are some general guidelines around sizing and some unique features of Accoya due to how it is manufactured.
| Application | Thickness | Width | Length |
| Natural Decking | 4/4, 5/4 S4S E4E | 6 (5.75″) | 8, 10, 12, 14, 16′ |
| Color Grey Decking | 4/4 (rgh), 5/4 S4S | 6 (5.75″) | 8, 10, 12, 14, 16′ |
| Lumber/Millwork | 4/4, 5/4, 6/4, 8/4, 10/4, 12/4 | 4-10″(12″limited) | 8, 10, 12, 14, 16′ |
Accoya sources the highest quality Radiata Pine which they refer to as A1 grade. This allows for up to 3 1/4″ pin knots per piece in material up to 6/4 thickness. For thicknesses above 6/4 up to 6 tight knots 1/2″ or smaller. Raw material is strictly sourced for straight boards with little to no wane, or side bend. Due to slight swelling during acetylation, Accoya finished and milled sizes allow for slightly larger than industry standard decking and nominal sizes. See 5.75″ wide above on 1×6 decking.
Why Accoya?
Acetylated wood is not new. In fact, many wood science courses at the university level have students creating acetylated wood. But Accoya is the first company to industrialize the process and allow for scalability. Their partnership with Eastman Chemical and investment in US based production facilities has earned them a Cradle to Cradle “Gold” certification, making them a truly net zero, renewable resource partner. Together, we are excited to push the boundaries of design and help to transform the great material made by Accoya into beautiful designs, homes, parks, and more.
