How much does a 4x4 wood post weigh?

Answer 1

An exact answer to your question is difficult because there are many factors that must be taken into account, but we can guestimate an answer.

Different types of wood have different densities. I believe that most of the posts sold in home improvement stores like Home Depot or Lowe's are Southern Yellow Pine or Cedar.

You have to also take into account the moisture content of the wood. Most treated wood sold at home improvement stores is Grade 2 and, when green, has a moisture content of 17% to 20%. You can feel the heaviness and moisture in the wood when you pick up a fresh post. This moisture in the wood adds a lot of weight.

And, of course, the length of the post makes a difference. For this example, we'll assume an 8' post.

Southern Yellow Pine (SYP) has a density of 36 to 41 pounds per cubic foot with a 20% moisture content. Naturally, as the wood dries out and with low humidity, it will weigh less. We'll use an average of 38.5 pounds per cu.ft.

Calculate the volume of wood. Actual (not nominal) size of the post is 3.5" x 3.5" x 96" = 1176 cubic inches. One cubic foot = 12" x 12" x 12" = 1728 cubic inches. Divide 1176 cu.in. by 1728 cu.in. = 0.6806 cubic feet.

Calculate weight. 0.6806 cu.ft. x 38.5 pounds per cu.ft. = 26.20 pounds.

So, a 8' 4x4 post made out of SYP with a moisture content of around 20% weighs somewhere in the neighborhood of 26 pounds.

HTH.

Answer 2

20 lbs