Plywood boasts excellent screw-holding power, high strength, and is characterized by its sturdiness, sound absorption, and heat insulation. It also has a low moisture content (between 10% and 13%), is easy to process, and has the widest range of applications.
Plywood is more stable than solid wood, but it is susceptible to moisture damage. Therefore, its use should be avoided in kitchens and bathrooms during construction.
Plywood processing methods include machine splicing and hand splicing. Hand splicing involves manually inserting wood strips into the plywood. The wood strips experience less compressive force, resulting in uneven splicing, large gaps, and poor nail-holding power. It cannot be sawn and is only suitable for certain sub-projects in decoration, such as underlayment for solid wood flooring. Machine splicing, on the other hand, experiences greater compressive force, resulting in minimal gaps, smooth splicing, even load-bearing capacity, and a compact structure that is less prone to deformation over long-term use.
Due to differences in material, quality varies. Plywood is classified into "superior grade," "first grade," and "qualified grade" based on the quality of the material and the texture of the surface veneer. Some companies label their boards as Grade A, Double A, or Triple A, but this is merely a business practice and does not comply with national standards; such labeling is no longer permitted in the market.
There are many types of wood used for plywood, such as poplar, birch, pine, and paulownia. Among them, poplar and birch are considered the best, as they are dense, neither too soft nor too hard, have strong nail-holding power, and are not easily deformed. Paulownia, on the other hand, is very light and soft, absorbs a lot of moisture, has poor nail-holding power, and is difficult to dry. Boards made from paulownia are prone to cracking and warping when the moisture evaporates during use. Pine, being hard, is difficult to press, has poor splicing structure, poor nail-holding power, and a high deformation coefficient.