# post holes, concrete and water



## rr (Dec 3, 2002)

Howdy from one of little knowledge but lots of backed-up jobs to do.
I'm putting in some 8-foot 4x4s three feet deep -- good enough for what I need. . I don't have enough of these to rent a mixer, but my rotator cuffs don't want me to mix by hand. How likely is it that it will suffice to dump the bags of concrete in the hole, then add water? I already have the concrete, and it's a standard sidewalk-kind of mix.
Thanks very much.
l


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## mtman (Sep 2, 2004)

there is only 1 way better thats iff the dirt is moist just put the cement in the hole then cover the rest with dirt it will be hard by tomorrow


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## Up North (Nov 29, 2005)

It will not suffice. Concrete must be mixed if it is to have any strength or bonding properties. For small jobs we mix it in a wheelbarrow using a garden hoe to stir it. If you are physically unable to mix by hand, seek the assistance of someone that is able. Otherwise just tamp gravel tightly around posts and save concrete for another job.


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## suzyhomemaker09 (Sep 24, 2004)

When we set fenceposts with concrete once upon a time..we used a thing called an oddjob...it was a conatainer made specifically for mixing concrete...add bag of mix...add water, put on lod and roll it across the yard..taa daaa....ready to pour mix.


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## Farmerwilly2 (Oct 14, 2006)

In your case, with a bum shoulder, I'll agree with MtMan, dump it dry into the post hole, ground moisture will set it. It's not a load bearing wall, it's a fence post. In my case and what I'd suggest to others in this area is if you can't drive them in (the best way) I'd agree with UpNorth and not waste good concrete on a fence post (I don't mind using other folks money when putting in their fence posts, just too tight with mine). Old farmer Tony taught me as a kid to rock 'em in place: a little dirt, a layer of our abundant limestone, then tamp hell out of it. Repeat. Holds tight enough that our friend, backing up her car, snapped a post off rather than pushing it over.


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## SectorSteve (Nov 29, 2003)

It worked for me. I live in Central Florida and 9 years ago I built 287 feet of 6' privacy fence that way. Dug the hole, dumped in half a bag of cement, poured in some water, dumped in the other half a bag , a little more water, tamp it down with a stick, covered it with dirt and walk away. BTW, be sure the post is true and plumb when you finish cause after a day or two, you won't move it. My fence has lasted thorugh a couple of hurricanes so I guess it works.
Steve


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## egads1 (Jun 7, 2005)

You can also do what's called "dry pack", set your fence post in the hole and dump the concrete in dry, pack it down, and cover with dirt. After a few rain storms the concrete will set. I've set a number of posts this way and never had a probelm.


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## Windy in Kansas (Jun 16, 2002)

The last I knew it was recommended NOT to set treated 4 X 4s into concrete to stabilize them as it promoted rotting at the concrete/soil line. The last I knew the only ones still advocating its use were concrete mix promoters and those behind the times. 

Best to check around before you set the posts and have to prematurely replace them.


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## Cabin Fever (May 10, 2002)

Do not, I repeat, do not, seal the end of the post in concrete. You can place cured concrete below the post as a pad. Or, you can place the the bottom portion of the post in soil or gravel and then pour concrete around the post...but never, even embed the end of the post in concrete. The end of the post needs to "breathe" and allow any wicked up moisture to escape thru the end of the post. If you embed the end grain of the post into concrete it will seal the post and the end of the post will rot away.


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## artificer (Feb 26, 2007)

I work with a person that tested the dry concrete idea out.  Short answer is the concrete will eventually get just as strong as normally mixed concrete.

If you can't mix the concrete because of the bad cuff, how are you digging the holes and backfilling? If using a skid steer or 3pt auger, then using the concrete will let you do it yourself. You definitely will not be able to tamp properly for the dry pack method.

If you use this method, I would suggest bracing the posts, and don't use them for a week, just to be safe. The wet the hole, pour in some, pour in some water, and pour in some more mix method would be good. Don't use too much water, or the section that gets the water poured on will be weaker. If you want good bonding of the concrete to the posts, partially drive some large galvanized nails into the bottom sides of the posts. Overkill, but it's your call.

I would add my endorsement of the dry pack method, if you can get help. I'm ornery enough and independent enough that I don't seem able to ask for help. In that case, I'd probably go with the dry concrete method. You've already gotten the materials, so unless you have another use for the concrete, go for it.

Michael


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## Hammer4 (Oct 13, 2005)

I set all my wood fence posts by digging the hole, setting the post, add some dirt and true it up, then fill with concrete, pour a bucket of water on it, done. 

That includes little 4x4 posts for our 4 foot fence around the backyard for our toddler to 8 inch corner posts h braced for 6 & 8 strand high tensile electric fence. It works great for me.


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## ColumbiaSC. (Nov 25, 2005)

I have set Many post, the easiest way I have done it, with great success is dig the hole, pour it about a3rd full of water, put the post in, dump in the dry redi mix cement then, get it right with the string straight line I.E. first and last post ( I set the string low to the ground), plumb up the post. I wet a shovel handle and jab at the mix to stir it up, check it again for plum and move on to the next hole/post. Let that set for 24 hours and start building. PS the longer the cement takes to harden the harder it will be, so if you use too much water just wait and extra day or so no problems. If it is too loose throw some dirt around the post or brace it off.
It will work fine not to pre mix the cement in a wheel barrow.


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## rr (Dec 3, 2002)

Wow, lots of help. I think I'll do this without screwing it up now.
Michael, I have a little tractor with a loader and a backhoe, which made the holes. I'm hoping I can tamp with something attached to the loader -- with care that should work.
If not, that motion isn't nearly as hard on my shoulders as pulling a hoe back and forth to mix concrete.
Again, many thanks.
rr


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## zukgod (Jan 28, 2007)

You don't need to mix the concrete. When they build pole barns they dig the hole toss in the pole throw in a bag or 2 of concrete and cover it up with dirt. No water needs to be added, it will get enough water from the soil and rain and in a day or so hard as well concrete. Fence builders do it exaclty the same way. Good luck.


Josh


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## farminghandyman (Mar 4, 2005)

use a premix concrete bag, that has the rock and sand mixed in, not jsut plain type one (I)or two (II) cement with out the gravel or rock and sand,

if you choose to just buy cement, when adding to the hole place on shovel of cement and then few of gravel, and then some more of cement and alternate, tamp the mix together with a steel pipe or shaft, (tamp as you fill from the bottom up not jsut from on top) 

the best tamper I have made is a length of shaft about 2' long welded onto a pipe, about 1" in diameter [3/4" pipe], and then a round piece of steel 3" x 3/4" thick piece welded on to the pipe end, the weight is about right, total length is about 5' long, and the large end will help compress lose fill, and then turn over and finish with the small end,


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## floyd (Apr 22, 2015)

I have never tried the dry concrete in the post hole then add water. But I am going to next post I set.


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## Bearfootfarm (Jul 13, 2006)

Pouring it in dry and pouring in some water works fine, but simply backfilling and tamping the dirt usually gets the same results.

I wouldn't anchor them too well because 4 x 4's tend to warp and twist so may need moving or replacing soon


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## fordy (Sep 13, 2003)

floyd said:


> I have never tried the dry concrete in the post hole then add water. But I am going to next post I set.


 ...........The problem with this method , is that , IF the ground is very dry , it will absorb a lot of the water that the concrete needs , to set up ! I have used this method successfully , but , I first filled each hole full of water early in the morning , then I came back and started setting posts by adding sufficient water to allow the cement to fully complete it's hardening cycle . 
...........Also , you would be wise to fully coat each post with roofing tar up to ground level for obvious reasons . , fordy


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## sisterpine (May 9, 2004)

I expect that here in the desert we would be waiting at least six months for there to be enough rain to wet the stuff naturally.


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## Cabin Fever (May 10, 2002)

I've built two concrete block chimneys on dry cement foundations. Both chimneys are still standing, one was a two story chimney. We mixed the concrete with just enough water so it would pack. This is just a tiny amount of water so the mixture is like moist soil.

We placed the concrete in a 3x3x3 foot form, 6" at a time. We packed each 6" layer separately. When the form was filled with the dry mix, we started building the chimney on top of it the same day. Mother Nature eventually cured the concrete into a solid block.


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## Bearfootfarm (Jul 13, 2006)

A common method of building retaining walls for culverts around here is to simply stack bags of ready mixed concrete as you would lay cinderblocks, and letting them harden on their own.

Sometimes folks will spray the stacked bags with a little diesel fuel to help waterproof the exposed paper to keep it from becoming too soggy before the concrete sets.

Water vapor in the air is enough to make the mix harden over time


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## lgrandmaitre (Feb 21, 2016)

Cabin Fever said:


> Do not, I repeat, do not, seal the end of the post in concrete. You can place cured concrete below the post as a pad. Or, you can place the the bottom portion of the post in soil or gravel and then pour concrete around the post...but never, even embed the end of the post in concrete. The end of the post needs to "breathe" and allow any wicked up moisture to escape thru the end of the post. If you embed the end grain of the post into concrete it will seal the post and the end of the post will rot away.


I know friends who use Tar paper around posts before setting so the post wont rot , I'm from northern canada


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## rambler (Jan 20, 2004)

rr said:


> Howdy from one of little knowledge but lots of backed-up jobs to do.
> I'm putting in some 8-foot 4x4s three feet deep -- good enough for what I need. . I don't have enough of these to rent a mixer, but my rotator cuffs don't want me to mix by hand. How likely is it that it will suffice to dump the bags of concrete in the hole, then add water? I already have the concrete, and it's a standard sidewalk-kind of mix.
> Thanks very much.
> l


In my soils and my climate it is much better to just pack the dirt around the post. When set in concrete, posts rot off faster than normal 'here' and our dirt is so heavy there is no need for the concrete to hold them. So 'here' you would be best off with no concrete at all.

If this is a post for a building that needs to hold the roof down, then a small ring of concrete near the bottom of the post works well. But you still would not want the concrete up near the surface 'here'.

In general your plan of dry premix and let rainfall soak it up will work fine if concrete on a wood post works there.

Paul


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## Fishindude (May 19, 2015)

I know a little about concrete, poured about 1,200 cubic yards this week.
While many do go the route of dumping the bag in the hole dry, that is absolutely an incorrect method of using concrete. It's just s short cut, lazy way of doing the job.

To get full strength out of concrete it needs to be mixed per the instructions on the bag, then poured around the post. 

Nothing wrong with encasing those treated posts in concrete either. They will probably outlast you. Modern treated lumber is pretty good stuff.


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## JoePa (Mar 14, 2013)

I agree - if you are going to do something - do it right - and that's mixing the concrete the way it is suppose to be mixed - I tore my rotator cuff a couple years ago when I fell off the back of my pickup truck - but I just kept doing what I always did and in time it hardy bothers me when I work hard using that arm and shoulder - don't baby it and the muscles will get strong to support any weight - and I'm in my 80s -


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## Bearfootfarm (Jul 13, 2006)

Fishindude said:


> I know a little about concrete, poured about 1,200 cubic yards this week.
> While many do go the route of dumping the bag in the hole dry, that is absolutely an incorrect method of using concrete. It's just s short cut, lazy way of doing the job.
> 
> To get full strength out of concrete it needs to be mixed per the instructions on the bag, then poured around the post.
> ...


It may be an "incorrect method", but really all it's doing is filling a hole, so strength doesn't much matter. "Properly mixed" concrete is very difficult to get down a small hole compared to a dry powder



> It's just s *short cut*, lazy way of doing the job.


That is exactly what the OP wanted


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## potter28 (Sep 10, 2014)

Your correct dumping some dry concrete in the holes and adding water will be fine. I would stir it up a little with a digging iron or stick, just be sure the top is level. As some other commenters have said it is not recommended to pour cement around the post due to them rotting off as it traps water against the post. Had this happen on my own fence. I believe its now code here in PA to do it that way anymore. Deck post holes are drilled 12-18" wide , 36" deep and 12" thick concrete then the post sit on top and are backfilled with dirt. Pole barns are done the same way.


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## motdaugrnds (Jul 3, 2002)

I've set posts in a variety of ways. The fencing posts I like to stabilize with large rock (plenty around here) on each side, fill the hole about 1/3 up and then dump in about 20 lbs of quickrete. Sometimes I just cover all this with the soil that came out of the hole. (If I cannot find the right size of large rocks, I will use an iron rod I have to dig rocks out of the soil with to mix the concrete up well...mixing it while in the hole...)

With studs that are going to be fixtures stabilizing a building, I place either a large flat rock on the bottom of the hole OR a large piece of treat wood on the bottom; then I set the stud on that, stabilize it with large rock and "mix" the concrete with water for a thick substance to fill the hole with.

I've also done the lazy way, i.e. stabilize the post to an upright position, add some water, pour the dry concrete in the hole and cover with soil. These posts have been standing now for over 15 yrs.


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