How To Set Pressure Treated 4x4 Wood Posts In Concrete (VERY STRONG!)

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This video will show you a great trick for how to set VERY STRONG 4x4 pressure treated ground posts in concrete! Keep in mind, this tricks will work for nearly any 4x4 pressure treated ground post you embed in concrete--whether you're setting a mailbox, fence posts, or other garden structures. (I've been using this trick for nearly a decade as a professional carpenter. It seriously helps solve the problem of wobbly 4x4 ground posts!)

Check out our other DECK-RELATED VIDEOS linked below!

Replace Deck Handrails:
Fix Loose Deck Nails:
Replace Deck Balusters:

Tool List:
Drill / Driver
Post Level
Margin Trowel

Material List:
50 lbs. concrete
3" exterior screws
4x4 pressure treated post

How-To:
1. Set pressure treated 4x4 wood post in post hole and mark ground level
2. Embed exterior grade screws in 4x4 post at angle below ground level marks
3. Place 4x4 post upright in post hole.
4. Level 4x4 wood post in both directions using a "post level" tool. Make sure bubbles on both sides of tool are between
4. Pour concrete around 4x4 wood post
5. Trowel concrete into slope around 4x4 post (this will help shed water away from post, prolonging its lifespan)

The reason this trick works so well is that the exterior grade screws embedded in the post act as anchors in the concrete boot surrounding them. In order for the 4x4 wood post to lean, it must wrench the entire weight of the concrete out of position, which is unlikely. It also helps negate the problem of the post shrinking and separating from the concrete--something that happens frequently when you use wet pressure treated 4x4 lumber for your ground posts!

For more articles on home repair and carpentry, visit my blog!

[zjedinite]

I’ve been doing this for YEARS! It just made common sense to me. I just use 1/2 rebar since I always have prices left over. I mass cut them at 4” I drill about 1” 1/2 deep using a 15/32 drill bit. Rebar goes in with a gentle tap of the hammer. I use this for ALL corner post and railings like this guy. I feel sorry for the poor sap that needs to remove my post. Strong post without Cialis! 🤣🤣🤣

[erikbogart]

I will use 8" #4 rebar, drill a 1/2 hole through the post 2" apart 1 going each way. If you are using a proper 12" hole the will leave the rebar 2" clearance on each side from the soil. It's called uplift protection and we have to include it on pole building construction. I use post to the ground as my handrail stanchions, so I always do it on my perimeter and stair case posts.

To your other point about leaving the concrete down from finish grade, here we have freeze and thaw cycles. If you don't leave your concrete down 6" surface freeze can and will get under the flare at the top and raise the concrete up. I've seen it grab 6" concrete bollards and raise them 4" in a single season.
I've never taken the time to slope the cap away from the post, but that is good work, I'm always happy to see someone who does something better than I do it, today I have gained another step at becoming the best. You had me by 1 for sure

[johnnycasady]

No matter how smart I think I am, somebody comes along with a simple idea that blows me away.

[Jaydayallday]

Nice trick. Thinking that even would help fence post that is holding gate.

[plainolamerican]

I enjoy your videos young man. Just a hint about those levels, the yellow plastic tabs in the center are for your rubber band, slip knot one on one side and it will stay on. all you have to do is pull it around your post and hook it on the other tab.

[morningthunder]

Great tip!
When I set posts for decks or stair railings, I take a 3/8” auger bit and drill holes at roughly 45 degrees and drive 3/8” rebar through the posts into the ground surrounding the post. If you do this on two sides, you can plumb the post easily before pouring concrete and the concrete, when poured, surrounds the rebar, but generally the rebar extends through the concrete into the earth. I walked away from many jobs knowing that the work was solid and secured.

[birdog]

For an extra heavy duty post (for a gate or handrail), use galvanized lag bolts and dig the base of the hole wider than the top. Frost heave won't push it up, and the lag bolts lock it down. You can also give the part of the post that will be below grade a coating of blackjack and allow it to dry before sinking them.

[grinpick]

Good advice. Also I always try to stand the post up off the ground at the bottom with a piece of concrete or stone which is smaller than the bottom of the post. (A doby block works well for a 6x6.) This results in the concrete flowing under the post. Without this step the wood post is resting directly on dirt, which does not support it as well as the concrete would. This is more significant when the post is going to support a heavy vertical load and yes, granted, this step would be less important when you're using screws to lock the post to the concrete, as you suggest. Might seem like overkill, but if you're hoping for that post to be solid for 25-30 years it could make the difference. And it costs very little extra in time or money.

[scottiver]

Post level only works on short straight posts. Most posts are NOT perfectly straight. Using a tiny 8" long level will not work for longer posts (fence posts) you need at least a 4ft long level to bridge any deviations or curves in the post. (40 yrs experience)

[lewishall]

Nice tip, I like to have a layer of gravel in the bottom of the hole and poly/paint just the bottom of the post, gives a capiliary break to stop the wood still pulling water upwards like its still part of a tree

[rogerenscore]

Neat tip, Ethan! My daughter told me to check out your channel and I've already learned a couple of helpful things. I'll be watching for more.

[raywalsh]

Thanks set tons of post and never thought of this.

[rico]

I’ve set a lot of posts in my time and never done it like that. That’s a damn good idea! Thank you keep up the good work!! 👍👍👍😎🇨🇱

[johnkirkwood]

Thank you Ethan. Just getting ready to set a couple “F” shaped kayak racks I made with with 4 x 4 support posts. I was concerned because of the stress the kayaks will create on the post settings and possibility of eventual slanting. This is an awesome idea. Thank you!

[tba]

Great idea. Will employ this idea for the two 4x4 posts going in the ground for hammock support.

[matthewkubik]

Used to tear out a lot of fence, and the post that were next to impossible to get out were the corner post that the old timers took worn old cultivator sweeps and nailed on upside down to the below grade portion of the post. They acted just like barbs on a fish hook! Those post refused to come out of the ground!

[troylee]

Good idea, I dig out the bottom bigger than the top, soak the bottom with oil and tar and drive landscaping spikes in the post just as he did. I had to remove some two years ago and they looked like the day I set them. Zero decay fifteen years later. They call me Overkill lol

[ryans.]

I've used that trick for years. Really works.

[normferguson]

I had to remove a 4x4 post that the original installer had put anchoring screws into 40 years earlier. It took chains and a car jack to pull it out of the compacted dirt and most of an afternoon. I said a few choice words about that concept.

[richlewis]

Thanks for the video. I actually knew about the screw/nail "tree" to lock the post in, and have done that successfully with a climbing/swing structure in the past. The real find here was learning about that "post level." I ordered one right away.