Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


4 inch round posts

4 inch round posts

4 inch round posts

   I need some help on making some posts.  I am making 4 inch round posts and I am new to concrete, if anyone could help me on the best mix and what rebar I would need.  The posts will be used in mexico so frost is not a issue. The posts will not be under any tension or extreme forces. They are just to fence in a acreage.   Any help would be appreciated, thanks

RE: 4 inch round posts

For a non-loading use - probably a single #4 bar down the center would suffice.

Are you hammering these into place or digging a hole and inserting them?

RE: 4 inch round posts

Thanks for the reply, I was hoping I could get away with a single bar and not a 3 bar spread. Labour is cheap here so they will all be going in by hand.

RE: 4 inch round posts

I am all for putting more concrete out in the world, but is there any particular reason you want to use a concrete post? I would think standard steel posts would be more cost efficient?


RE: 4 inch round posts

Steel posts flex alot unless you go with a sch 40 wall or larger.  Which gets pretty expensive.  

RE: 4 inch round posts

Fair enough, how are connecting your fencing to the posts?

With your cheap labor, I assume you are mixing your own concrete. Planning using a bag mix (quikcrete) or mixing your own with portland and local sand and gravel?

What will you use for forms? Build a reuseable wood for or cardboard throw aways?

RE: 4 inch round posts

Yes I am mixing my own concrete, I just cut a 4 and half inch pipe in half and welded some angle iron to seperate it.  I was thinking about using a 60 percent gravel to 40 percent sand mixture.  Thanks for any advice.

RE: 4 inch round posts

And I am just wrapping sheep fence around them so I am not fastening anything to the posts

RE: 4 inch round posts

Outdoor concrete - if you are in a cold climate you should also consider air entrainment to avoid freeze-thaw damage.

RE: 4 inch round posts

I am in mexico, so if freeze becomes a issue fence posts will be the least of my concerns.  Because there is very little load on the posts do you think I could get away with #3 rebar, #4 is not sold in the closest town.  Thanks.  And do you guys agree that a 60% gravel to 40% sand ratio is alright.  I am from a hydraulic background so I know little to  nothing about concrete, I am from way Northern Canada where we rarely use concrete.  I will be making a bunch of other concrete items, is there any formulas to figuring out rebar.

RE: 4 inch round posts


We dont usually specifiy the exact concrete mix as these are usually proprietary mixes that are designed and tested by the manufacturer.

I have specified a mix on a few smaller jobs where it is mixed by hand. Cement :Sand : aggregate

1:2:4 for a nice durable mix
1:3:6 for a leaner much cheaper mix (at the sacrifice of durability)

Water content should be no more than about 60% of the cement.

RE: 4 inch round posts

How about using 4" pvc ,grouted. I'd be interested in any comments on whether you'd need reo bar in it ,the tensile strength of the pvc seems to be pretty high and I would imagine being on the outside would have good resistance to deflection. cheap too and no rust.Iv'e used it on tap stands (4 ft high) 2" dia. pvc with fibre reo and their very solid.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close