Plywood Versus Solid Wood

Here is an overview of plywood versus solid wood and how they compare in terms of strength, applications, and working properties.

Plywood

Plywood is a manufactured wood product that is made from multiple layers or plies of thin solid wood that are glued together to form a panel of a specific thickness. The plies are oriented so that the grain direction in one ply is rotated 90° relative to adjacent plies. This enhances both the strength and dimensional stability of the plywood. There is usually an odd number of plies in a sheet of plywood.

Plywood is most commonly sold in thicknesses ranging from approximately 3/16 to 3/4 of an inch. A standard sheet of plywood measures 4 feet wide by 8 feet long, although 5' x 8' oversized plywood, can also be custom ordered.

Plywood is made from both softwoods and hardwoods and is available in a number of grades based on the quality of the face and back veneers. For example, A grade plywood is practically free from all defects in the face and back veneers whereas X grade plywood has plenty of knots, knotholes, cracks and other defects



Solid Wood

Solid wood lumber is produced from slabs of wood that are sawn from logs and then kiln dried. The drying process not only reduces the moisture content of the wood but also increases its strength and dimensional stability. However, even after kiln drying, solid wood will shrink and expand dimensionally in response to seasonal fluctuations in atmospheric humidity.

Grading standards for solid wood lumber are a bit more complex than those for plywood. They differ depending on whether the wood is a softwood or hardwood, and may include the structural integrity of the wood as well as appearance.

Applications

Plywood is ideal for applications that require sheet material that is not susceptible to cracking, shrinking, or warping. Examples include cabinets, desktops, and storage containers. Plywood also works well for creating curved surfaces such as skateboard ramps.

Solid wood has been used as a building material for thousands of years and it really shines in applications where strength and stiffness matter including bookshelves, decking, and structural supports, such as floor joists and roof rafters. It is also the material of choice when aesthetics and beauty really count.

Solid wood is often used in combination with plywood. For example, a desktop or shelf made from plywood will often have solid wood edging on it to conceal the unsightly plywood edges. Another example is solid wood support strips used to stiffen a plywood shelf.

Strength and Stiffness

Solid wood is significantly stronger than plywood, especially in terms of stiffness. A shelf made from solid wood will sag less than one made from plywood of the same dimensions.

If solid wood furniture is not properly designed, it will weaken over time due to the wood movement related to changes in atmospheric humidity. In extreme cases, cracking and splitting of the wood can occur. Plywood does not do this. However, plywood layers may separate in a damp environment.

Woodworking Considerations

Plywood is relatively easy to rip to width but can be challenging to crosscut due to tear out of the thin outer layers of veneer. When sanding plywood, care must be taken not to sand through the veneer, especially when sanding near the edges.

The additional time and effort involved in applying edging strips needs to be taken into account when building furniture with plywood.

Solid wood is relatively easy to rip and crosscut although pinching of the saw blade can occur when ripping stock with internal stresses. Solid wood can also be planed to make it thinner, something that is not feasible with plywood.