I was curious if anyone has ever tried applying creosote on the portion of a post that would be buried in the ground. Not very many naturally rot resistant species around here. (Locust, Cedar, Hedge, etc). Pressure treated lumber is out of sight pricewise. Looking for a cheaper alternative that I can do with my mill and trees I do have access to.
Never done it. A coating of roofing tar might work. One problem I see is the rest of the wood remains hydroscopic allowing water in and it may stay soaked below ground. Sort of like when you paint masonry.
Gleaned from another forum... 'I make up 15 gallons at a time. I have a Vat for dipping posts in, made from an old tank cut in two,8 feet long. Works great.Here's my recipe. 5 gallons of coal tar roofing or driveway sealer, 5 gallons of Diesel Fuel 5 gallons of burned Diesel oil,2 lbs of feed salt Stir well with an old shovel. You can simply dip about 2 feet of your post in a bucket of this formula, or dip the entire post in the vat.Soak for a couple hours.For use on boards, simply get an old pump sprayer, or use a paint roller. Wear long sleeve clothing. On some board fencing, I've poured in a gallon of cheaper oil based black paint in the mixture to help it flow.Lasts for years.In some hot climates it may fade a little quicker. No liability written, expressed or implied.'
I used creosote on fence posts over 40 years ago. It was on natural wood fence posts and it made it last longer than natural fence posts but not nearly as long as PT which I have used since. NowI'd never go with creosote vs PT but that could be just me.
Ive used roofing cement on 4x4's. Isnt oak heartwood rather rot resistant? Cherry and black walnut heartwood are as well.
Another old school trick is to char the ends of the posts that are going in the ground. Build a small fire and rotate the post ends a few times until blackened all the way around. A torch (no, not a flashlight you Brits ) works too.
Creosote posts here are ridiculously pricey. 8’ x 4” $14 8’ x 5” $18 8’ x 6” $22 Osage posts are anywhere from $15 - $50 depending on length & dia.
