I am building a split-rail fence out of locust rails and posts. The posts
will be set about 8 feet apart. I plan to dig postholes about 18 inches
deep, and set the posts into concrete.
What is the best method, and type of concrete ? My thinking was to use
Quickcrete fast-setting concrete. With similar things in the past, I have
mixed the concrete with water, and poured the mix in and around the post.
But, it seems that I have heard that other folks just pour the dry power in
the hole around the post, and allow the moisture in the surrounding soil to
harden the mix. Others pour in dry, and then just add a modest amount of
water in the hole.
What is the preferred method ??
Thanks for any advice on this !!
Your 18" post hole seems way too shallow for a fence. Better do some
more research on local conditions and methods and then worry about
concrete mix. Typically, some metal fence posts are 7' tall and 3'
into the ground. For a relatively short fence 2' would be a good
Let's please stick with the concrete question.... these posts will be 18
inches into the ground, and about 40 inches OUT of the ground. Split rails
will be placed across the posts. This is a simple three rail fence, not a
conventional fence with 6 foot posts.
Perhaps I led you wrong on the facts.
The best concrete to set posts is none. A couple inches of gravel in
the bottom and ALL the dirt back in the hole is the "proper" method.
And 18" is too shallow; a waste of, time, effort, money -and- concrete
if you're still set on using it. 30" is minimum and probably code,
and 36" is better.
Locust is the best choice for the posts, but you'd be better off
setting them on fire rather than in concrete. Nothing lasts forever,
try digging out a post set in concrete. By the time you're finished
you'll have changed your mind, if you live through it.
The concrete mix doesn't matter, any one will rot your posts as well
I guess I will at least answer your question -
Most big home centers carry "post-set" concrete. You dig the hole,
put the post in (with space around it) fill the space around the post
with dry mix, add water, and mix it up by pushing a pc of rebar up and
down in the "soup". Sets quickly, works fine and is very convenient.
Sorry, but I must respectfully disagree about putting dry mix in the
I have seen this done, but I have never seen it work well - fences
were always leaning within 3 or 4 months. It is not possible to
mix the concrete in the hole - there will always be dry pockets no
matter how much poking and prodding is done.
Mix your concrete in a wheelbarrow and pour it into the hole.
Just curious, but when the wood rots away, how will you replace it? And,
you've been told (more than once) that the depth you've chosen isn't deep
enough, yet you insist on not heeding advice. You seem to have the answers,
so which one would you prefer to be told about the concrete?
If OP INSITS on concreting them in secure them in place, tied off with
ropes or something, use dry mix its more convenient, leave set tied up
a week or so flood area a couple times, so its all hardened
I would agree. But any set in concrete should not be set completely in
concrete- a couple inches of gravel in bottom, then post, then 1/3 or so of
the hole with tamped gravel, then concrete. Give the water a place to go,
instead of bottom of post always being wet. Locust takes awhile to rot, but
anything rots eventually.
TX hill country. Fractured limestone is immediately below the soil. Only a
rock bar and alot of sweat, or, a diamond tipped auger can cut it. 18" is
typical depth for corner and tensioning posts on typical pasture fence.
Wood or steel posts.
Guess answers for this are kinda like gardening, depends on the
conditions... Sandy soil, clay, swamp, gravel, or rocky in your case.
I pre-mixed, wetter than usual, the concrete prior to pouring in the hole
with the post. Used rocks to stabilize the post during the pour, then fine
tuned the plumb after the pour. Set the corners first.
Because I used rocks inside the holes to stabilize the posts before the
pour. Wetter concrete assured me I had complete concrete saturation around
and under those rocks. No cavitation due to too dry a mix for that
situation. I used the inverted mushroom hole type. No gravel on bottom.
Stabilized bottom with suitably sized rocks, then top allowing at least 2"
above that topmost rock to concrete surface. Used level for plumb both
After the pour, I re-checked plumb and made minor adjustments if needed.
I did the tensioning posts similarly, except, I used a 3/4" offset
stringline for alignment with corners bottom and top. Stringline used for
rough, removed, then installed again after pour for final alignment. Of
course, the 90 degree opposite direction plumb was with a level.
A few neighbors in the area said to go with 5000 psi bagged concrete instead
of the 3000 psi version. They said they had no cracking problems with it
over time. Makes sense as sometimes 2 feet or more of the limestone rocks
will displace when using a rock pick or auger at the surface. Leaving
bigger area (hole) at surface to pour. Can't be helped. So, I used that
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.