Accoya® Color Grey Decking

Hewn specializes in creating wood products that can withstand the toughest environmental conditions, with proper care and maintenance. For our Decking products, we exclusively utilize Accoya® due to its proven track record of durability and stability, making it an excellent alternative to cedar, tropical hardwood, or synthetic decking options.

As the first company to produce acetylated wood on a commercial scale, Accoya® is leading the charge in providing durable and dimensionally stable wood for a variety of applications. In the acetylation process, softwood is essentially turned into a hardwood through the introduction of a non-toxic vinegar-like solution, creating a new type of wood that is durable all the way through the board, not just on the surface. 

In practice, this allows for a wood product that is significantly protected against the elements, making it perfect for installation in exterior environments where a standard sealed wood product would fail after only a short amount of time.


Accoya® Decking Specifications


Widths:1×6 (5 ½” actual)
Thickness: 1”


Greater than 9 rating per AWPA E7

Moisture Content

3-5 % at 65% relative humidity, 20°C

Density and Spread

65% RH, 20°C, Average 32 pcf, Range 27 to 37 pcf

Fire Rating

Class C (ASTM E84) and D (EN14915)

Thermal Conductivity

ASTM C177, = 0.102 – 0.120 W/m∙K

Janka Hardness

ASTM E143, Tangential = 972 psi, End Grain = 1,484 psi


Approved by WDMA as compliant with WDMA I.S. 4. Certified as compliant with Cradle-To-Cradle with Platinum Level Material Health Certificate.

Fastening System

Our Accoya® Decking products are milled with our custom profile, designed to utilize our clip-based fastening system for easy and consistent installation. Our clips are made of Marine Grade 316 Stainless Steel, with sharp points that embed into the upper portion of the groove for strength and stability. The matching stainless-steel screws ensure a solid connection point to your joists. A joist every 12″ is recommended.


Decking Milling Profile

Our custom Accoya® Decking milling profile is designed to utilize our clip-based fastening system, aiding in an easy and consistent installation process.

Face: 5 ½″
Actual Dimensions: 1″ x 5 ½″

Endless Versatility of Accoya®

The uniquely durable properties of Accoya®, created using an all-natural process, allow the wood to be utilized for a variety of purposes. Our sales representatives can customize your order to fit your precise needs and use-case scenarios.

Exterior Siding

Sealed for optimal protection against the elements

Interior Paneling

Durable enough for high-traffic commercial areas


Insect and rot resistance in a real-wood product

Joist Tape

Hewn and Accoya® recommend using Protecto Deck Joist Tape during the installation process. Protecto Deck Joise Tape is a self-adhering, cold-applied tape used as flashing on deck ledger boards and joists to help prevent moisture penetration around properly installed fasteners. Deck Joist Tape also provides a non-corrosive barrier between treated lumber and metal hangers. Its Super Stick Technology™ adhesive doesn’t require a primer and can be applied down to -20°F (-28°C) and high temperature applications. 

Protecto Deck Joist Tape is sold separately from your Hewn purchase, and can be sourced from major building supply retailers.