Don’t preserve wet wood

Q: I am building a fence, and I want to put preservative on the posts. The man at the hardware store said that I can’t use the preservative on green wood, and that’s what I have. — Bob

A: “Green” is the term used to describe wood which has not dried. Wood that contains water is less apt to absorb additional moisture. So, it is less able to absorb a sufficient amount of a preservative.

Unfortunately, most folks do not consider treating fence posts, so the ones that air-dry naturally while waiting to be sold are not in great demand, and for that reason the store where they were purchased would probably accept a return or an exchange for drier ones.

The lighter in weight, the drier the post. Actually, most folks equate heavy wood with strong wood, but that is not the case when wet wood is involved. After-construction drying, and the shrinkage that follows the use of green lumber, can do much to diminish the appearance or quality of your project.

Since you live in California, we assume that you are using redwood, and for that reason we would not be alarmed if you elected to proceed without the chemical treatment.

Whatever you do, don’t use Douglas fir posts unless they are factory pressure-treated. Locally treated fir simply deteriorates much too quickly.