You have probably heard of plywood and you almost certainly have plywood in your home (even if you don’t realise it). However, few people are aware of what plywood is, and its many uses in DIY, carpentry and construction. In this series we will tell you everything you need to know about plywood, and how you can use it in your home with great effect.
What is plywood?
Plywood is a composite wood product made by bonding multiple thin layers, or 'plies,' of softwood or hardwood. Plywood is usually made from an odd number of layers and the grain of each layer runs at right angles to the previous layer, making the plywood incredibly strong as well as reducing shrinkage. This process is known as cross-graining and it means that, while some wooden finishes may split or shrink with time as they dry out, plywood maintains a more uniform finish.
What are the different types of plywood?
As with most building and carpentry materials, there are different types of plywood made from different types of wood. The most common types of plywood include softwood plywood, hardwood plywood, MDF core, marine plywood and birch plywood.
Softwood plywood is made from layers of softer wood such as cedar, pine or spruce. Softwood plywood comes in a range of varieties, including sanded pine for a high-quality finish, or CDX, which is strong and water resistant so suitable for external use.
Hardwood ply is made up of veneers from wood from deciduous trees, such as oak, maple or birch, which produce harder wood. Subcategories of hardwood ply include Birch, which has a high strength to weight ratio, making it ideal for quality cabinetry, Oak plywood, which offers an attractive grain so is used for decorative purposes, and maple, whose light colour and uniform grain make it a preferred material for furniture and cabinets.
Marine plywood is designed to withstand high levels of moisture and is used for boat construction or outdoor projects. The adhesive in marine plywood is water and boil-proof (WBP) so that layers remain stuck together, even under exposure to water. Marine ply is made of layers of hardwood that are dense and have low water absorption qualities. Because marine ply is made without any gaps, water is less likely to get trapped between the layers, which could cause the wood to rot.
Plywood is also graded A-D and describes the strength and appearance of the wood.
Plywood can vary in cost and it is not necessarily the case that the more expensive product is better; different plywood types are better suited to different products. If you are unsure of what plywood will look and act the best in a project, speak to a local carpenter.
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