Read that cedar fence posts can last 40 years if you treat the bottom foot

Found it in a forestry extension guide from the University of Minnesota. I've been using the same ground contact rated stuff for everything, but they say a specific copper naphthenate soak makes a huge difference. Anyone have a good source for that treatment or a different method that's worked long term?

3 comments

3 Comments

finley_smith10h ago

Hold on, that copper naphthenate advice is a total pain. Diesel fuel? That's nasty stuff to work with and a real fire risk. The ground contact rated lumber you're already using is fine. They make it to last. Soaking posts for a day is a huge waste of time when you could just buy the right wood and be done with it. I've seen plenty of cedar posts go in with nothing special and they're still solid after decades. This sounds like making a simple job way too hard.

wyattramirez12h ago

Saw a guy on a homesteading forum who built a pole barn. He soaked the cedar posts in copper naphthenate for a full day. Said he mixed it five percent in diesel fuel. Claims it's the only thing that really stops the rot at the ground line.

emma_lee227h ago

That five percent mix is actually pretty standard for ground contact, but you're right about the diesel being a pain. A lot of guys just use a heavy motor oil instead, it's less volatile and works almost as well.