12mm Exterior Grade Class 3 Hardwood Plywood 2440mm x 1220mm (8' x 4')

What is 12mm Exterior Grade Class 3 Hardwood Plywood?

12mm Exterior Grade Class 3 Hardwood Plywood (2440mm x 1220mm) is a strong, stable, and versatile panel conforming to EN 314-2 Class 3 and EN 636-3 S standards. Its properties suit it to numerous applications in construction, including flooring underlayment, hoardings, and general utility work.

It is vital to understand that 'Exterior Grade' (defined by EN 314-2 Class 3 glue and EN 636-3 usage class) refers to the durability of the glue bond and the panel's potential suitability for exterior conditions. It does not mean the wood itself is waterproof or immune to decay. The hardwood veneers, while potentially possessing some natural durability, will absorb moisture, swell, shrink, check (crack), and eventually decay if left unprotected. 

Therefore, for any exterior application or where exposure to moisture/humidity is expected, thorough sealing of all faces, backs, and especially edges is absolutely essential for long-term performance.

Composition and Construction

• Hardwood Veneers: The panel is constructed from multiple thin layers (plies or veneers) derived from hardwood timber species. Hardwoods generally offer greater density, strength, and durability compared to softwoods. 
• Cross-Laminated Structure: During manufacturing, the grain direction of adjacent veneers is typically oriented at right angles to each other. This cross-banding is fundamental to plywood's properties, providing enhanced dimensional stability (resistance to expansion/contraction), increased resistance to splitting, and improved stiffness across the panel compared to solid timber.  
• Adhesive Bonding (Class 3): The veneers are bonded together under heat and pressure using a thermosetting synthetic resin adhesive, specifically chosen for its high resistance to weather and moisture. This is crucial for its 'Exterior Grade' designation and complies with EN 314-2 Class 3 requirements.   
• Nominal Thickness: The panel has a nominal thickness of 12mm. This thickness provides adequate strength for many applications while remaining manageable.

Applications

• Floors
• Roofs
• Walls
• Hoardings
• Temporary Protection

Mandatory Sealing: For any exterior use, or where moisture/humidity is present, all faces, backs, and especially all edges MUST be thoroughly sealed with a suitable exterior-grade finish.

Benefits

• Unrivalled weatherproof properties ensure resilience against the elements.
• Smooth surface invites flawless finishing touches.
• Exceptional strength and durability uphold structural integrity over time.
• Immune to moisture, weathering, and fungal intrusions for long-term reliability.
• Wide-ranging applications cater to diverse project needs.

Why Seal? 

The Class 3 glue prevents delamination, but the wood veneers remain porous. Unsealed wood will absorb moisture, leading to swelling, shrinking, cracking, warping, and decay. Sealing creates a protective barrier.

Edges absorb moisture much faster than faces. Pay extra attention to sealing all cut edges, often requiring multiple coats.