Marine Plywood is manufactured from a selection of hardwood species. The board is normally manufactured with an odd number of plies, each ply being oriented at 90 degrees to the one bonded to it, to create a balanced construction. The face and reverse veneers are almost always oriented in the direction of the longest dimension. Marine Grade plywood differs from most other hardwood plywood’s in 4 specific ways:

1. The hardwood species are from a select group, known to be naturally resistant to fungal decay and beetle larvae infestation. BS 1088 describes “Standard Marine Plywood” as “made throughout of timbers having a durability of Class 3, BS EN 350-2 or better” with a minimum nominal density >500 kg/m3. BS 1088 also allows for a “Lightweight Marine Plywood” of durability Class 4, BS EN 350-2, or better and of density <500 kg/m3. In either case, up to 5% sapwood is permitted in any veneer.
2. The quality of the core veneers is generally the same as the face, regarding the absence of open defects, resulting in a virtually solid panel with few core voids. This is a guide only and BS 1088 is specific regarding the actual type, size and frequency of the defects permitted in outer and inner plies.
3. The standard specifies minimum thickness of veneer: outer plies minimum 1mm after sanding; inner plies maximum of 4.8mm for panels more than 3.8mm nominal thickness. In practice, inner plies are generally thinner. This gives rise to a greater number of thinner veneers than many other plywoods. More veneers require more glue lines, thus increasing the glue content of the panel giving rise to greater stability. In panels of 6.5mm or less, a minimum of 3 plies is required.
4. The proportion of veneer oriented with the grain parallel to the face must be between 40% and 65% of the nominal, unsanded thickness of the panel.

BS EN 314 is a standard for plywood bonding quality, divided into two parts: Part 1 (BS EN 314-1) details test methods for bond strength, while Part 2 (BS EN 314-2) specifies requirements for bonding classes (Class 1 for dry, Class 2 for humid, Class 3 for exterior/weather conditions) based on end-use, ensuring plywood adhesives meet performance needs for different environments, like structural or marine applications. This product is EN 314-2 Class 3.

Bonding Classes (from BS EN 314-2)

• Class 1: For dry interior conditions.
• Class 2: For humid conditions, protected exterior uses, or damp interior uses with limited moisture exposure.
• Class 3: For exterior conditions, exposed to weather or continuous high humidity (e.g., Marine Plywood).

BS EN 636 is the standard for specifying plywood suitable for structural use in dry, humid, or exterior conditions. The classification determines the plywood's durability and suitability for different applications. This product is EN 636 Class 3.

• EN 636 Class 1: Suitable for use in dry interior conditions only, with low humidity.
• EN 636 Class 2: Suitable for use in humid conditions, which can include protected exterior applications where the plywood is not directly exposed to the elements.
• EN 636 Class 3: Suitable for exterior applications that are fully exposed to the weather and ground contact.