What is three-ply plywood?
Three-ply plywood is a panel made of three layers of veneer glued with their grain at right angles: the two outer faces run in the same direction and the core runs across them. This cross-lamination makes the panel far more stable than solid wood and less prone to warping. With only three plies, true three-ply is thin and light. In Dutch it is called triplex.
Three-ply, multi-ply and 3-layer solid wood panels
- Three-ply is the simplest form of plywood; thicker plywood has five, seven or more plies. Thin birch plywood of 4 mm, for example, is typically three-ply, while thicker sheets have more plies.
- Do not confuse it with a 3-layer solid wood panel (German Dreischichtplatte): that is a thicker board made of three layers of glued solid timber strips rather than veneers, used for furniture, wall lining and formwork.
Bonding: interior or exterior
The adhesive determines where you can use the board. In Europe, EN 314-2 defines bonding classes from class 1 (dry interior) through class 2 (humid or protected exterior) to class 3 (exterior). Marine plywood is a separate, higher-grade product. Remember that a waterproof glue does not make a non-durable timber species rot-resistant.
Uses
- Cabinet backs and drawer bottoms.
- Model making, architectural models and crafts.
- Lining walls, ceilings and door panels.
- Templates and jigs.
- Interior fit-out of caravans and boats (exterior-bonded).
Practical tips
- Cutting: use a fine-toothed blade and put masking tape over the cut line to stop the thin face veneer from splintering.
- Fixing: thin plywood holds screws poorly near the edges; glue and pin it, or screw through it into a batten behind.
- Storage: store sheets flat and dry, or they will bow.
- Sanding: the face plies are thin, so sand lightly to avoid going through the veneer.
Related terms
- Plywood
- Veneer
- Sheet material
- Film-faced plywood
- Wood glue
- MDF
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