Wood fence post coated with tar?

Before I planted my fence posts, I coated the bottom of the posts with that tar-like black stuff that you can coat driveways with. Driveway sealer of some sort, black, tar-based. I don't really know what if any difference it will make. I bought mine in a 5 gallon bucket at Home Depot for somewhere around $20 or so.

:-)

on 4/21/2009 11:25 PM (ET) Zootal wrote the following:

Better to use a special tar mix that is used to coat the concrete walls below grade before backfilling. Most times it is brushed on then heavy plastic sheeting is stuck to the tar to provide additional waterproofing. It is available at the big box stores, and may be available in smaller stores.

Somehow I doubt it would do much good and was probably done to impress the fence installer's client. Tar coating the wood would do little to prevent water from eventually soaking the bottom of the post and little to prevent decay. Once water got into the wood the tar probably would slow down the wicking away of the water during dry periods enhancing rot. If it isn't a substance that soaks deep into the wood and also kills the rot fungus it will do little else.