The wood that stops behaving like wood outdoors.
Accoya® siding, run through our texturing line and finish line at Rigby, Idaho. Published prices by finish level. Delivered on our trucks, priced by the mile.
Accoya® is acetylated wood. Accsys Technologies takes fast-grown radiata pine and converts the wood's free hydroxyl groups to acetyl groups, right through the board. The wood stops absorbing water, so rot fungi and insects lose both their food and their water pathway. It is not a coating and not a pressure-treated preservative. It is a change to the chemistry of the wood itself, which is why Accsys can warrant it for 50 years above ground.
Accsys makes the material. We buy it, and then we do the part a distributor cannot: mill it to profile, run it through the texturing line, and finish it on a conveyor-fed finish line from a stored recipe, so board four hundred matches board four.
One board. Four ways to finish it.
The four boards below are renderings of the four finishes we offer. Colour on a screen is a direction, not a match. Confirm every finish with a physical sample before you commit a wall.
Swatches and the house below are renderings. Screens shift colour and no picture settles a finish. Order the samples before you commit a wall.
Pick the finish level, the colour, and the wall.
Priced per covered square foot of wall, which is what you actually buy and what you can compare. Delivery is priced by the one way road mile from Rigby on our own trucks, $4.00 a mile per load. Orders of 8,000 square feet and up get a firm price and delivery date within one business day. Smaller orders we price by hand in the same window.
Mill finish and Textured ship clear sealed in Natural only. Colour applies to the finished levels.
Published prices are a starting point by finish level. Trade pricing is applied at the time of order, never as a credit account, PO terms or net 30. Payment in full is due before anything leaves the mill. Every order is confirmed by our team within one business day before anything is cut.
Milled, textured and finished before it leaves Rigby.
Siding and soffit
Milled to profile, textured, and finished before it leaves the mill. Accsys requires a ventilated cavity behind Accoya siding, a quarter inch to three quarters of an inch depending on climate zone, to keep the warranty intact. We detail to that requirement and say so on the submittal.
Decking and stair treads
Covered by an ICC-ES evaluation report at service condition UC4A. Note the warranty split below before you spec a coloured deck board.
Trim, millwork and windows
Dimensional stability is the reason Accoya shows up in window and door work. Movement on a 145 mm board, green to oven dry, runs about 1.0 mm radial and 2.2 mm tangential, with a 3.6 mm warranty maximum.
Screens, gates and fences
Same board, same finish recipe, cut to your drawing, so the fence reads as part of the house instead of an afterthought bolted on later.
Published specification data
Every figure below is published by Accsys Technologies for Accoya. None of it is ours, and none of it is estimated. Ask us for the source document on any line.
| Species | Radiata pine, acetylated |
| Durability | Class 1 to EN 350-1 for Use Classes 1 through 4 |
| Janka hardness | 922 lbf side, ASTM D143 |
| Density | 515 ± 80 kg/m³ at 65% RH and 20°C, about 32 lb/ft³ |
| Equilibrium moisture content | 3 to 5% at 65% RH and 68°F |
| Shrinkage, wet to 65% RH | 0.4% radial, 0.8% tangential |
| Movement, 145 mm board, green to oven dry | 1.0 mm radial, 2.2 mm tangential typical; 3.6 mm warranty maximum |
| Modulus of elasticity | 1,297,492 psi to ASTM D143 (about 8,950 MPa) |
| Thermal conductivity | 0.12 W/m·K to EN 12664 |
| Structural grades | A1 at strength class C22, A2 at C16, per German DIBt approval |
| Fire, untreated | Class C to ASTM E84, tested at Southwest Research Institute. |
| Lead time | 2 to 4 weeks from an approved shop drawing, by finish level. Your exact date is confirmed at the order. |
Fire, said straight
Untreated Accoya is Class C to ASTM E84, tested at Southwest Research Institute. Anyone selling you untreated Accoya as Class A is wrong.
A Class A rating needs a separate fire-retardant treatment, and Accsys publishes a warning that certain fire-retardant chemicals can invalidate the Accoya warranty. Treated Class A Accoya is published by other converters for interior use only.
For wildland urban interface work in Summit, Wasatch, Teton and Gallatin counties, the route that actually holds up is the tested assembly, not a treated board. ICC NTA tested Accoya siding to ASTM E2707, the ten minute direct flame test, and it passed in a specific named assembly: minimum two by four studs, five eighths inch DensGlass Gold sheathing, butt joints caulked with 3M Fire Block Sealant FB 136, a minimum three eighths inch cavity, and three quarter inch or one inch tongue and groove Accoya. Spec the assembly, not the adjective.
The warranty, with its conditions
Accsys warrants Accoya for 50 years above ground and 25 years in ground contact and freshwater immersion. That warranty is issued by Accsys, not by us, and it is governed by the Accoya Certificate of Warranty. The conditions matter:
- Siding needs a ventilated cavity, a quarter inch to three quarters of an inch by climate zone.
- Through-body colour decking is not covered for 50 years. Accsys publishes 25 years residential, and 10 years for commercial use and for residential use in Florida.
- Exposure to products above pH 9 can invalidate the warranty.
- Certain fire-retardant chemicals can invalidate the warranty.
- Salt water splash zones are covered, but attack by marine organisms is not.
We will put the certificate and the conditions in your submittal package rather than printing a number on a brochure and letting you find the fine print later.
Certifications an architect will ask for
Cradle to Cradle Certified® Gold
With Material Health at Platinum, and Gold for product circularity, social fairness, water and soil stewardship, and clean air and climate protection. Covers Accoya and Accoya Color Grey.
FSC®
Accsys holds FSC certification under code C012330. A chain-of-custody claim on finished product requires the converter's own certificate, so ask us where our certificate stands before you write FSC into the spec.
Declare label and EPD
International Living Future Institute Declare label for Accoya and Accoya Color Grey, plus a published Environmental Product Declaration.
ICC-ES, DIBt, FCBA, KOMO
ICC-ES evaluation report for decking and stair treads at UC4A. German DIBt structural approval. FCBA certificate of conformity with factory audits every six months. KOMO approved quality system.
What we will not claim: PEFC, which Accsys does not publish for Accoya, and a VOC figure, which we have not seen a document for. When we have the document, the number goes on this page.
Where we stand with Accsys, plainly
Accoya® is a registered trademark of Accsys Technologies, and the material is made at Accsys plants in Arnhem, Netherlands and Kingsport, Tennessee. We do not make it and we do not claim to. Acetylation happens at an Accsys plant. Milling, texturing and finishing happen at ours.
Accsys runs an Approved Manufacturer program. We will say on this page the day we hold that status, and not a day before it. In the meantime what we offer is straightforward: we buy Accoya, we mill and finish it well, and we publish Accsys' data honestly rather than rounding it in our favour.
Also in Accoya: outdoor floating shelves, made to size and in stock through Ultra Shelf, our shelf and mantel line.
Part of a family of American manufacturers
Snake River Hardwoods is the hardwood mill of Murphy Door® Inc., milling textured hardwood, veneer, siding, and edgebanding in Rigby, Idaho, and shipping to all fifty states.