Dating pressure treated lumber
Because every tree is different, individual pieces of lumber will show a wide range of quality in strength.
To ensure that the right kind of lumber is used for the right job, the U. Department of Commerce established the American Softwood Lumber Standard.
Softwood lumber also absorbs and loses moisture much easier than hardwoods, so extra care must be taken to maintain the wood’s stability over a lifetime.
Big box hardware stores don’t stock much of it though, so you’ll often have to visit a specialty woodworking store or a lumberyard to purchase it.