Most of us already know that a 2x4 isn’t really a 2x4, it’s more like 1½ by 3½. But does anyone really know why that is? We went on a hunt to get to the bottom of this construction mystery. One of the answers we found was that it’s just the lumber industry saving some bucks on their milling size, which could make sense if we didn’t find a couple of other better reasons. For instance, the dimensional lumber we use in construction nowadays is milled and planed so it has a nicer finish and is possibly more resilient to its new environment. The other one we found was that lumber is kiln dried to help it dry evenly as well as maintain its shape - when it gets dried out a bit the wood shrinks!
To read more about 2x4’s check out the link below: