What Determines the Strength + Weight of Plywood?

What Factors Determine the Strength + Weight of Plywood?

The general rule with plywood panels is the more plies, the stronger. But ply number varies by tree. So how do we know? Typically:

• ¼" plywood has 3-5 plies
• ½" plywood has 5-7 plies
• ¾" plywood has 7-9 plies

Variables like thickness, length, and how much support is added all work to determine how much weight a project panel can hold. Here are some basic guidelines regarding strength and the importance of adequately supporting longer lengths of plywood for your DIY wood projects:

• Plywood with fewer than 4 layers has the least strength and should not be relied on to hold much weight without support
• Plywood with 4-7 layers is moderately strong and can be used with the proper support for shelves, cabinets, and most other home projects
• Plywood with more than 7 layers is the strongest and is best for heavy-duty projects

To increase the weight that thinner, longer project wood panels can hold, add support. For example, a thick, short piece of plywood, like a ¾" 2' x 2', can hold 50-100 lbs. unsupported. But a thinner, longer piece, like a ½" 2' x 4', can only hold about 30-40 lbs. even when supported at both ends. To hold 100+ lbs., add support along the long side of your wood project panels too.

Many factors also determine how much a plywood panel will weigh. You can find a specifications section on almost every retailer's product webpage with details like weight, dimensions, etc.

Still, because wood is a natural product that varies by species and individual tree, there's no way to accurately state the precise weight of any plywood project panel before purchasing it. Any listed weights should be considered an estimate and may be off by many lbs. depending on the panel.