I am building a fence by myself and was wondering if 4x4 pressure treated posts will be sufficient to support my 5ft gates?

I would use 6x6 but they are going to bee too heavy for me to handle by myself.

I live in the southeast USA and will sink the posts 2ft here in the Georgia clay for a 6ft tall fence.

  • 1
    Include a diagram of the fence in question as well as the width and rough weight or construction of the gate. The adjoining structure provides rigidity and is often adequate to hold the weight, but sometimes it's nice to upgrade the support post (sometimes a deeper footing depth instead of thicker post) if it's free standing or supports a particularly heavy gate. 4x4 seems to be fairly adequate for standard gates up to 3.5 feet (Meaning a square with a kitty corner cross with fenceboards mounted to it. Depending on the ground layout you can also put a wheel on the gate.
    – K H
    May 7, 2021 at 2:40
  • If you want enduring fence posts, definitely consider using 2 or 3 inch metal pipe. Seems to last indefinitely, just have to replace the boards now and then, although you need special brackets unless you want a good neighbour fence.
    – K H
    May 7, 2021 at 2:41
  • 1
    Having 6' exposed and only 2' buried, especially as the gate posts seems to be inviting imminent collapse whether it's a 4x4 or a 6x6. There's a lot of strain on the posts as the gates swing, and you'll want those support posts to be as sturdy as possible. You may consider bribing, er, hiring a couple of neighbors (pizza and beverages) to help you heft taller posts into the holes, even if it's only for these two.
    – FreeMan
    May 7, 2021 at 13:49

5 Answers 5


If your gates are wooden, they will sag1. Even if your gates are metal, they may sag. I would recommend 6x6 if you can manage to find a friend, but I would also recommend you sink them 3ft into the ground if they're 6ft tall above ground.

To deal with sagging, use metal cables that can be shortened/tightened, either with clamps at the end where you can periodically unclamp and tighten the metal cables, or with a metal cable turnbuckle/tension hook in the middle somewhere that you can tighten without having to detach first.

There are already other excellent posts on this site about how to hang a fence post to prevent sagging based on the material used.

1: If you don't believe me, last year I built a custom fence in Georgia using 1x4s for the panels (with hog wire sandwiched between two 1x4s) and 4x4 posts; 4ft tall fence with 2ft buried in concrete footings. The gate panels are 4ft wide. Alone, the gate panels are maybe 5 pounds... which is very light for a gate. Less than 1 year later and the gates have started sagging; not much, maybe 1/16th out of level, but it's noticeable when you look at it up close. I also cut one gate to be a pretty snug fit, and it has since started scraping against the latching post a bit, which again indicates sagging over time.

(For reference, I used this hinge hardware: 8 in. Black Heavy-Duty Decorative Strap Hinges by Everbilt)


2' is not very deep for a gate post. I would check that with an expert who understands your ground conditions.

You only need to move one end of the post at a time, so you only need to lift half its weight.

If you pay for delivery of the posts the delivery truck will probably have a crane on it and can drop them into the holes for you.

  • Depends on the height of the fence/gate. For a standard 4' fence/gate, 2' is plenty (if encased in concrete). However if OP wants a 6' fence/gate, I would recommend 3' in ground. This also doesn't seem to address the question asked, which is whether to use 4x4 or 6x6 posts.
    – TylerH
    May 8, 2021 at 9:36
  • the answer to that depends on how strong the timber is and how big and heavy the gate is
    – Jasen
    May 8, 2021 at 10:25

4x4 post taller than 4ft in high humidity with more weight on one side pulling it down will sag a little. Once I built a wooden basketball goal and in less than a year it bent over almost touching the ground. 6x6 post need a lot more leverage to bend.


Based on what farmers use for gates, I would say that 4x4 is not large enouh. I think that it will flex. If I was doing it, I would use 200mm round, so slightly larger than 6x6.

I am more concerned about the depth. Just dropping the post in hole will not work. Farmers would ram it in to the ground. I think a 3rd of its height is the norm. So I would go at least 3ft deep, but concrete it, in a hole, which 2 to 3 times wider than the post.

Our current gate post is concrete blocks sitting on a foundation around a timber post rammed in 3ft. After 5 years, it is already out of plumb. At our previous place, the engineer had specified 4 timber posts rammed in till they would not go further. That was overkill, but the brick gate posts did not move!

A lot depends on the soil, we have clay soil around here.


I recall the old ranches near my grandparents' house. They would set up two sets of posts: proximal posts for the gate hinges and the gate clasps (or the reciprocating gate), then distal posts about 6 feet out, cross-braced by another set of timbers. A 6x6 more than doubles the amount of material, and the strength, which still may not be enough depending exactly what kind of gate you're fitting!

Sadly the best example I can readily find on the Internet is rather dilapidated and lores, but if you squint you can make it out! enter image description here

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