Question about concrete around a treated post

[Steve Nelson]

Your right Steve, I have several set in concrete for my patio and they have been there 17 years and are shoing no signs of decay or instability.....Steve

[Jack Diemer]

I have set a bunch of posts in concrete without problem. I would dig the hole, pour in quickcrete, and then add water and stirred until it was thick like pudding. (Sounds like I might have done it wrong).

[Herb Kelley]

Our second house had an owner built deck.
After a while we notived that a corner of the deck had started to sag.
Looked at the 4x4 treated post and the concrete that surrounded the hole.
Nothing looked strange. Just must be settling I thought. Started jacking away. The deck came up and up with the post until the rotted end of the post became visable. The post had been slowly rotting away inside the concrete and sinking under the weight of the deck.
Seems like the deck must have been up about eight years until it had gotten that bad.

[Brad Risley]

The trick with puting fence posts in conctrete is to bring the top surface of the concrete above the ground surface. Slope the concrete down and away from the post. What happens is that the water pools on the concrete surface and rots the post. Another trick is to coat the post section that will contact the ground and then several inches above that with brushable roofing tar/cement. Also seal the tops of the posts with the same tar/cement to stop the end grain from absorbing water and rotting the post top. I just replaced 300ft of 30 year old fence treated with tar. The posts were fine at and below ground level but the exposed upper surfaces had just about weathered away.

[Bob Weisner]

Thanks for all the replys. I think I will go with the posts resting on a concrete footer, instead of encasing them in concrete.

Bob

[Steve Clardy]

Yeah, I did dig out all the old 4x4s w/attached concrete...will NOT do that again! Hey, post #3000....

Well you gotta post a 100 times a day to catch up with Becker though.
I'll never catch you two unless you all evaporate on me.

[Gary Sutherland]

I've heard in the past that in addition to the concrete being poured to slightly above ground level, you should set the post on a base of gravel in the bottom of the hole before pouring the concrete around it. This allows drainage of moisture around the wood. Anyone tried this? Does it work?

I am about to build a heavy wooden fence, and was planning on using this method (with pressure treated posts).

gary

[Chris Padilla]

Read the whole thread, Gary...that is precisely what I did on a fence I built about 8 years ago...but my posts were untreated Redwood.

[Ed Hardin]

I think if you read the lable on treated posts, you will probably be warned against putting them in the ground. I know I took the time to do so and found that to be the case with my treated wood. Now if you are using creosote, who needs concrete. If you are applying creosote be verrrrrrry careful. That stuff will blister you to a fair thee well.

[James Carmichael]

Has anyone ever seen a wooden power pole set in concrete?

I have never had to replace a fence post set in packed dirt, stone, and sand, but I have replaced many set in concrete (including a few I did myself in my youth).

I will have to second that, and I live in an area of bogsucking black gumbo clay that is home to an average of 26 termite colonies per surface acre. I've had fenceposts set in concrete snap at the base in a heavy wind yet pulled unset landscape timber fenceposts that had been in the ground 20 years and could have been reused. The problem around here is, if you don't set, shifting is guaranteed. I think most of the problems occur when a poor job is done to where the concrete can't drain and traps water around it's top. I go an extra step and treat the post bases with roofing cement.

[Dennis McCullen]

Lots of good suggestions here! Food for thought - How long will the "Simpson" harware last? I hope a long time since I used them for my carport 4X6s. I especially like the suggestions about gravel in the bottom of the hole and then raise concrete above grade level to channel water away. Perhaps coating base with tar will help also. What I have not seen, and maybe this is obvious to everyone, is the treat level provided. Some stores sell both above ground lumer treated to 0.25% and ground contact at 0.40%. Yet suppliers to agriculture are quick to point out that they supply 0.60% treated poles and posts and have some products available at 0.80%. These higher levels are "guaranteed" for 30 years, but we all know that might be, at best, replacing the defective post or pole and not involve the near insurmountable task of getting the defective pole out from under a camp. So, my 2 cents worth is that if necessary to put posts into concrete follow all the suggestions that help channel moiture away.

Additionally, there are "sleeves" available made of heavy-duty plastic that will keep moisture away from in-ground treated posts. They are pricey and I'm not sure if they are yet proven, but seem to be a good idea. The plastic sleeves for 6 X 6 posts for example go on the post before setting it in the ground and extend to above grade. The are 3-4 ft long, have a couple of weep holes in the bottom?? and can be trimmed to accommodate trimwork for dressing out the posts. I know someone who bought them for around $35 each to go around 6 X 6 square poles that were deep treated 0.6%. These were the main supports for a pole building, a camp, being built on a raised bed of red clay. I believe since the clay bed puts him well above grade, this will prove sound for at least the 30 years.

[Virgil Johnson]

If you choose to use treated lumber set into the ground...


First make a footing (below frost level if needed- check local codes for depth and footing size) on undisturbed earth.
Be sure to use rebar - concrete has compressive strength and steel has tensile strength. (read cracking and splitting without steel)

Be sure the rebar is encased in the concrete (at least two inches at the edges) or the steel will rust away.

Use a connector to keep the post from drifting.

Be sure to use treated lumber rated for ground contact - most big box store treated 4x4s are not. Look at the label!

(Not all treated lumber is the same.)

Do not bury in concrete - it will trap moisture as the wood shrinks.
This will form a puddle of water that will drain but keeps the wood damp and allows oxygen to feed the bad guys.

Yes treated lumber will rot - just takes longer. Best to keep it drained (unless it is a pier set in water - like docks - always wet works well - think of ocean piers.)

Best to let the treated lumber dry for a few weeks before using.

Surround the post with crushed rock or the like to keep water from puddling.

Virgil

[William Addison]

I have never had a problem with treated posts set in concrete and my experience is that the 2X4 runners and pickets will go before the posts do.

Not the subject of this thread but I read where one person dug old posts out. There is a much easier way. I attach a tractor jack to the post with a chain or a nailer, prop it on the other side with a brace, wet the ground with a root feeder and just jack it out. A lot less work than digging and faster too. Rarely does the post pull out of the concrete but if does, wrap a chain under the mushroom and do the same thing.

[David Freed]

The post building manufacturer and installer near me sets their posts in concrete and their buildings are considered permanent structures. They have 300,000 sq ft under roof at their main plant, employ 150 people, sell and deliver to most states east of the Rockies, and have many years of experience building them.

With that said, I see no problem going the footer route either. I think it is more of a preference rather than one being better than the other.

[Lee Schierer]

While we are at it. Heres one I'll throw out here. Not to hijack your post Larry.

If building a deck and setting pressure treated posts in the ground surrounded by concrete is a no-no, [First I have heard of this being a no-no] then what about a pole building [which is what I have] that is basically the same thing. 6x6 treated posts set 3' deep surrounded in concrete.
These types of buildings are all over the country and have been for a long time. I have not heard of any falling down due to treated posts failing.

Curious Steve

I'm with you Steve, pole barns are quite common around here and other than one or two failing because they forgot to include snow load in their roof truss calculations, I've never hear of one collapsing. My pole barn is 20 plus years old now.