# "pouring" *dry* concrete



## Simpler Times

I was told once that for small slabs intended to bear little weight, you could put the concrete mix down dry and allow ground moisture to harden it (i.e., no mixing water).

Is anyone familiar with that technique?


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## DaleK

I've heard of people putting it down to harden the surface of the dirt. I think "slab" would be a bit grandiose a term. Water isn't that expensive or hard to come by.


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## chickenmommy

We use that method when putting in clothesline posts. Dig the hole , insert post, fill with concrete mix, water well. Works like a charm. Can't imagine a slab, though.

Sent from my Novo 10 Hero QuadCore using Homesteading Today mobile app


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## DEKE01

i don't think it is the availability of water, it is the difficulty of mixing concrete without a mixer. I have seen people in the Caribe islands pour cement on the ground to stabilize an area for foot traffic. I've seen people stack bags of cement around ditches and other areas to create walls. The bags absorb rain water and over time become solid, eventually the paper bag rots away. I doubt they have mixed concrete type strength, but they are strong enough to support heavy trucks going over a culvert.


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## wannalive

for a slab no... for a hole with a post, yes


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## fishhead

Whenever I've tried it in holes the concrete was always crumbly later.


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## fordy

.................For a fence post , one should atleast fill the hole with water and allow it to soak in then fill hole maybe 1/2 full before pouring in dry concrete . Pouring dry concrete into a completely dry hole is a complete waste of money ! , fordy


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## kentuckyhippie

my husband was a stonemason for over 40 years and I have seen him dig out a shallow depression where he wanted the slab then fill it with dry concrete or mortar then lay the flat stone on top, fill the cracks with dry concrete and sprinkle it with water and it would set up and some of the first ones are still fine after all this time so it does work. woudnt work for a slab that you were going to drive over but for foot traffic it works fine


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## highlands

Get a mixer and do it right. Even a little mixer like this one will let you do the job right:

http://sugarmtnfarm.com/2007/10/27/mixer/

We built our home in two months using that. I'm using it now again for some of the work on our butcher shop. Next step up is a barrel mixer. After that, get readymix delivered by the truck load.


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## Simpler Times

Yes, my concern is the labor involved in mixing by hand, not any lack of access to water. Wetting down the area prior to pouring in the dry mix would be easy enough to do but I am thinking ground level, without any excavation. I wonder if I could accomplish the same thing your husband did KH without surface stones, just by framing off an area with 2 x 6s's or 2 x 4s, wetting the frame and the ground under it down, dumping in the dry concrete mix, then leveling the surface with a rake or by running a long board over the edges of the framed in area to smooth out the mix?


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## TNHermit

Concrete poured like that will be the strongest and hardest stuff you ever seen. Put a piece of plastic over the opt till it hardens. Done for strength lots of time. And its the reason you keep your slump as low as possible when you do wet instead of the self leveling slop they pour nowdays


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## Shrek

When I took the rain gutters off my house 15 years ago I picked up 500 pounds of concrete mix and turned it into the soil under the eaves with a tiller to make dirtcrete to prevent trenching near the house foundation from roof runoff.

Grass growth on the 3 foot wide dirtcrete is still minimal and it is only showing small areas of water trenching beginning but I plan to have my maintenance man work some more concrete into my splash zone in the next couple weeks to provide another decade of gutter cleaning freedom to me.


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## joebill

Shrek, I betcha the grass and trenching is in dirt that has blown in on top of your dirtcrete......Joe


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## kentuckyhippie

Simpler Times said:


> Yes, my concern is the labor involved in mixing by hand, not any lack of access to water. Wetting down the area prior to pouring in the dry mix would be easy enough to do but I am thinking ground level, without any excavation. I wonder if I could accomplish the same thing your husband did KH without surface stones, just by framing off an area with 2 x 6s's or 2 x 4s, wetting the frame and the ground under it down, dumping in the dry concrete mix, then leveling the surface with a rake or by running a long board over the edges of the framed in area to smooth out the mix?


he did some sidewalks for us that way without the stone on top and they held up very well.


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## Shrek

joebill said:


> Shrek, I betcha the grass and trenching is in dirt that has blown in on top of your dirtcrete......Joe


You might be right. The reason I took the gutters off was because I have four white oak trees about 60 feet tall in my front yard canopying the west half of my house. For the life of me I cannot understand why the previous owner guttered this shack with that many trees canopying the front yard and half the house. 

Although I blow and rake the leaves from around the house every fall, some do remain to be mulch mowed in the spring, 15 years of orphaned leaves composting may have added to the creep grass layer over dirtcrete. Maybe I should try dragging a hoe around the house before having my maintenance man to pick up a dozen sacks of concrete to till in again.


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## dirtman

If you are using bags of quick crete or some pre-mixed crete then the least amount of water that will still coat the aggregate with cement will be your strongest concrete. The problem will be putting any kind of finish on it. You need to get a little "milk" to the surface to trowel it smooth. You may be able to smear a cement water slurry over the surface after the concrete has set a little but a couple of people with hoes and a wheelbarrow can easily mix up enough concrete to do a small slab.


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## fishhead

I don't think it costs that much to rent a mixer. You could even position it so you dump where you need it and then move it to the next place.


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## JoePa

If your going to do something - do it right - get a mixer and pour the concrete into forms which have metal meshing to strengthen the slab - then you can be proud of what you did -


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## swamp man

What, exactly, is the project? If you just need a little concrete and a truck can access the area, call the local 'crete companies. Sometimes you can get a bargain on a coupla' yards......the leftovers from a different delivery.
For a patio or stone walkway, I use a few inches of crushed limestone, tamp it, then use a dry mix of sand and Portland cement. It's easy to work with in terms of a leveling agent, and you don't need a float, which looks like a simple too, but will frustrate you to no end.
I do spray the patios down, and they lock up good. Like Fish (I think that's who it was) said, I think you'll likely end up with crumbly, weak 'crete if you rely on ground moisture.
DISCLAIMER! Technique described above works GREAT in South Mississippi 'cuz it don't beget cold enough to heave the ground. Not sure about your neck of the woods.


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## fishhead

So can you get it as hard using the dry method (leveling dry and then wetting in place) as you can doing a pour of mixed wet cement?


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## TNHermit

fishhead said:


> So can you get it as hard using the dry method (leveling dry and then wetting in place) as you can doing a pour of mixed wet cement?


Water is just a carrying agent mostly. The least slump you can work with is the best. I never go more than 4.

If you do it dry you mist it down and cover it up with a vapor barrier,tarp or what ever. It will take longer to harden. Its best use for small areas and regular low slump mix for larger areas


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## sammyd

a hoe and wheel barrow work quite well if you're mixing up for a small slab, done plenty like that, you could even splurge and get a proper mixing tool with the holes in the blade.


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## a'ightthen

Having eaten more concrete than most have poured ( 200-300 cu yds/wk for nearly 13 yrs), I never once encountered a concrete truck of dry mix. Low slump yes, even on a 100 degree day with 1% calcium added due to a shelter being set the next morning.

I suspect that there is a reason for this. Even the 8,000 psi poured in a truck parking lot was with water ... not dry with water sprayed later to enhance strength. I've also poured many a bag of QuiKrete without ever seeing anything other than " mix with water" on the bag.

I'm with Fordy on fence posts. I've also seen many a bag hardened due to just dew. Some set up hard, some are brittle - read about cold joints.

Ye speak of concerns with labor involved. Seek something more lasting ( assumed by using concrete) ... do it right and do it only once. Mix it up properly and be done with it.

I tend to picture someone sitting in a lawn chair spraying dry concrete with a garden hose and expecting a perfect slab ... it ain't like that. No degradation of your intent intended .... just what I pictured and it won't work.


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## a'ightthen

Adding that even with fence posts in the manner Fordy spoke of .... it's best to juke it ( basically mixing it in the hole).


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## where I want to

Something to think about is frost too. Although I have not done what you are saying, I did quite a bit of reading about it to see if I wanted to do it for garden walkways.
Two things were mentioned as problems- one was lots of rain which would wash away the unset levels of the concrete. The other was that it was it was not stable in a place where frost heave would be an issue.


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## plowhand

Well, I know you cant portland cement, and mix it in with soil or sand and have a floor strong enough for hogs..about a bag of portland to 9'square I think, 3" deep. Level and turn on sprinkler.
Another fella tilled up the shops dirt floor, hauled some sand, tiller it up, i disrember how many bags of portland, but he said it was about a quarter of what the cement truck would have cost. It was as hard and hardwearing as you'd want for a home workshop on a budget.


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## jwal10

My carport is 12'x20' I added 3" of sand on top of the packed crushed rock base that was done 15 years prior. Spread a sack of Portland cement for each square yard, mixed in with a garden rake. Screeded it off with a 2"x4" and watered it well with a fine mist from a hose nozzle. I have done this with many walk ways. I use a 2"x4" for the form, add sand and Portland cement. Water well....James


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## a'ightthen

But ye mixed it ... not the same as the perceived suggestion of breaking bags and watering .... ye made concrete and all was well eh?


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## TNHermit

If ya want to test it out take a bag of crete and or quick crete and let it set outside


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## a'ightthen

TNHermit said:


> If ya want to test it out take a bag of crete and or quick crete and let it set outside


 And yet again. research cold joints - it is what it is. Partial mix ain't concrete as it should be ... craftsmen should know better.


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## TNHermit

a'ightthen said:


> And yet again. research cold joints - it is what it is. Partial mix ain't concrete as it should be ... craftsmen should know better.


If you haven't noticed there is a big difference between what is done by farmers. professionals and alternate construction methods talked about on this forum. good luck trying to get everyone to do it your way


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## a'ightthen

It ain't about my way.

I quickly concede that ye are a master craftsman of wood ...

But ye will not cause me to sway from that which is proper .... and attempting to lackadaisically imply conformance to a substandard application without substantiation will not take place. Farmers and homesteaders are not hicks .... all should take heed of the instructions provided.

Please provide more information on your ways as prescribed by the manufacturer of your materials.


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## kasilofhome

educate me---

Ok--I have wondered about some soft spots==one is at and area in my driveway---

It is heavy traffic---it is just sand with gravel that goes missing each spring ---not last winter I used alot of coal ash--it is heavy and that area was firmer--so I was thinking of spreading a dry mix (tips for what I might use) to ready prevent another spring where the goo in a foot deep and I have to block the driveway to prevent cars from ending their life in the goo pits of kasilof.---I have had laced boot suck off miy feet ---I hate the dreaded break up season in Alaska.


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## TNHermit

a'ightthen said:


> It ain't about my way.
> 
> I quickly concede that ye are a master craftsman of wood ...
> 
> But ye will not cause me to sway from that which is proper .... and attempting to lackadaisically imply conformance to a substandard application without substantiation will not take place. Farmers and homesteaders are not hicks .... all should take heed of the instructions provided.
> 
> Please provide more information on your ways as prescribed by the manufacturer of your materials.


It might be good for you to know that I started my career of woodworking stacking Simmonds 2x4 steel forms for poured basements. Two years later I was job superintendent for a holiday Inn project. And it was as a working superintendent. No setting on your behind in those days. 
It again was stacking 2x4 Simmonds steel forms on jack post to pour the ceilings. I was taught by a farmer and a master concrete technician. Who today would probably get fired for the way they treated employees because they "taught" you and expected you to learn and were perfectionist. We hand troweled the finish. after using a power trowel. 

I,ve poured a few hundred yards of concrete. Maybe not as many as you. But I learned the dry method from the farmer. Not all instructions are written on a bag. I can take you out back and show you a 30 x60 slab that was puored by me and one hillbilly and to this day has only one hairline crack in it. Becasue I refuse to use fiberglass reenforced concrete . Its no good. And just for a little FYI I know the guy that first invented the front unloading truck which the unions hated because it killed their days of screwing around with the rear unloader up

All i really wanted to do from the start was work with the master trim carpenter they . I eventually got there  and learned the same way , It was a No BS back then. But it has served me well and those who worked for me over the years. Just because some manufacture says thus and so isnt the final word. Fiberglass concrete being proof of that. Ya can't get a good finish on it.
I've also pured whole barn floors where you spend the day and get that nice flat smooth finish and smile and the farmer comes in and says that's great . Then takes a rake and goes over the whole thing. So his cows don't slip . Lesson learned. Frankly I wonder some days when you see the slop that is poured how some buildings even stand


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## ronbre

several years ago we did an addition on our woodshed and we put down the cement dry and then we sprayed it down with water..really well..

it doesn't give you a pretty finish and isn't as smooth as finished concrete..but it is durable and easy to walk on ..not slippery..when there is snow and ice on it in the winter when you are messing with wood deliveries that are covered with snow..I appreaciate the lack of slipperiness as I'm a fall risk with my disabilities


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## ErinP

My tried and true method for concrete is the good old wheelbarrow, but for something the size of a slab, just call a truck and be done with it.


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## Ifaye

I want to make stepping stones between above ground tree roots.


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## Danaus29

You would get more notice if you started a new thread. Just click on the "start discussion" box near the top on the right.


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## Sebastian C

Shovel and a wheelbarrow. Mix with the appropriate amount of water. Pour, repeat, screed. Sprinkle dry cement on top and float smooth, or broom if you wish for more texture. 

If it's a bigger pour get a second wheelbarrow and a helper. If it's bigger than that get a truck. Renting a mixer is as much trouble as doing it by hand I'd think. 

I'm highly skeptical of wetting down dry mix and having it turn out well.


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## random

TNHermit said:


> Water is just a carrying agent mostly. The least slump you can work with is the best. I never go more than 4.
> 
> If you do it dry you mist it down and cover it up with a vapor barrier,tarp or what ever. It will take longer to harden. Its best use for small areas and regular low slump mix for larger areas


I'm wondering how that might work to help firm up (and help with weeds) my tractor parking area. I simply can't afford a slab right now due to many other house projects that have tapped the till, but I'd like to get SOMETHING in there.


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## Sebastian C

random said:


> I'm wondering how that might work to help firm up (and help with weeds) my tractor parking area. I simply can't afford a slab right now due to many other house projects that have tapped the till, but I'd like to get SOMETHING in there.


Geotextile and gravel, or here where I live they sell road material (lastre in Spanish) that is different size rocks or shale mixed with clay. That stuff doesn't need Geotextile. I dunno if that's available up north cuz I was a city boy until I left the states.


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## Fishindude

This is a very old thread, but it is NEVER a good idea to pour unmixed dry concrete / cement in place and expect it to do much.
It's probably OK to dump a dry bag in a post hole to stiffen it up a bit, but you can also do posts with no concrete at all. Pull that post years later and you will see the dry concrete that got dumped in the hole will be very soft and easy to bust away from the post with a hammer -vs- ready mixed wet concrete that was poured around a post.


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## RobertDane

Simpler Times said:


> I was told once that for small slabs intended to bear little weight you could put concrete mix down dry and allow ground moisture to harden it (ie no mixing water). Is anyone familiar with that technique?


I guess if you don't put anything on it..walk on it...Sure it will harden up. I've had quickcrete harden up 

in a sack that had set around for awhile...As far as durability...without some type of rebar..or maybe chicken

wire, it will just bust up into pieces...eventully...I knocked wet crete from the wheel barrel onto the 

gravel by the barn...sets-up and stays pretty much in one piece..


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## SpentPenny

DEKE01 said:


> i don't think it is the availability of water, it is the difficulty of mixing concrete without a mixer. I have seen people in the Caribe islands pour cement on the ground to stabilize an area for foot traffic. I've seen people stack bags of cement around ditches and other areas to create walls. The bags absorb rain water and over time become solid, eventually the paper bag rots away. I doubt they have mixed concrete type strength, but they are strong enough to support heavy trucks going over a culvert.


Those bags are special for that purpose. They are perforated so the water can get inside. Regular bags do not work nearly as well.


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