Siding Spec Page | Woodland Exteriors

Accoya wood is dimensionally stable, meaning it stays straight and true regardless of environmental conditions.

Backed by a 50-year warranty against rot and decay above ground and 25 years in ground or freshwater.

Accoya's dimensional stability helps paints and stains last longer, reducing cracking, peeling, and maintenance substantially.

Accoya offers exceptional resistance to rot, decay, and insect damage—without toxic wood preservatives.

Non-toxic and 100% recyclable, Accoya is the perfect material for environmentally conscious projects.

• Shiplap
• Tongue & Groove
• S4S: Available in squared-edge and eased edge.

Used for rainscreens, soffit and trim.

• 7/8 : 4" / 6" w
• 4/4 : 4" / 5" / 6" / 8" / 10" / 12" w

• 5/4 : 6" / 8" w

• 6/4 : 6" / 8" w

• 8/4 : 6" / 8" / 10" w

• 10/4 : 6" / 8" w

• 12/4 : 6" / 8" w

• 4/4 Accoya Color Gray: 6"

• 5/4 Accoya Color Gray: 5 3/4" (rounded corners for decking)

regulatory & material Class

Durability Class: Class 1 (EN 350-2) — Highest possible biological durability against wood-decaying fungi.

Use Class Classification: Use Class 3 (UC3) (EN 335 / AWPA U1) — For exterior, above-ground applications exposed to weather.

Thermal Conductivity: λ = 0.102 W/m⋅K (ASTM C177 / EN 12667) — Offers superior thermal insulation compared to standard softwoods and hardwoods.

Environmental Certifications: Cradle to Cradle (C2C) Gold Certified, FSC® Certified, LEED credit eligible (MR, IEQ), BREEAM compliant.

dimensional engineering & profiles

Thickness & Width Tolerances: EN 1313-1 compliant (± 1mm thickness, ± 2mm width maximum variation).

Profile Configurations: Standard Tongue & Groove (T&G), Shiplap, S4S Open-joint Rainscreen profiles, and bespoke architectural millwork profiles.

ARchitectural specification notes

Sub-Structure Design: Rain-screen principle applies. Must incorporate a minimum 20mm continuous ventilation cavity behind the cladding with insects/rodent mesh at intake and exhaust points.

Fastener Metallurgy: Structural requirement for Grade 304 (A2) or Grade 316 (A4) Stainless Steel fasteners only. Aluminum, galvanized, or carbon steel fasteners will suffer galvanic corrosion from the residual acetic acid.

Coating Compatibility: Compatible with water-based acrylic or alkyd-resin coatings. Film-forming coatings must have an elongation at break of >150% to account for micro-movements.