# Mixing and pouring concrete



## pengyou (Jun 22, 2009)

I am drawing up plans to build a small cabin, that will ultimately have a room added on to become my home. The foundation needs 4 cubic yards of concrete. I have free access to a mixer that can do 1 cubic yard at a time. 

Is it advisable to mix concrete by myself for this purpose? I have never done anything more than a wheelbarrow load of concrete.

My friend (the owner of the mixer) says to allow 1 hour to make up a new batch. Is it advisable to pour a foundation like this in 4 increments, each separated by an hour? I know that there are additives that will slow the hardening of the concrete. 

The foundation will have almost 2 months to cure before I begin construction.

Any ideas?


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## beowoulf90 (Jan 13, 2004)

An hour between mixes?

I know we poured my garage floor 12x24 mixing by hand in a 6x3 mixing tub. 
Now a few years later (at least 3) I haven't had any issues because of the different batches.. I don't think there would be any problems with this. Once it is poured you will till have to trowel it out and smooth it out. The concrete isn't going to dry in 4 hours...

But I'm not a contractor or anything.. Just a frugal homeowner..


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## pengyou (Jun 22, 2009)

Frugal homeowners' opinions are sometimes worth much more than a contractor's


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## ihuntgsps (Mar 10, 2008)

The answer depends on if the foundation is a poured concrete foundation resting on a footing below frost line. Or is the foundation you are talking about a poured concrete slap with maybe a 18" or so "rat barrier"?

It is not advisable to pour a slab in multiple pours.

If you can get a concrete truck into your building site and pour it all at once it will save you lots of time/forming/etc. and you will have a better end product. Concrete in my area (3500lb mix - 5000lb mix) would cost you under $520 including delivery.


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## jwal10 (Jun 5, 2010)

How do you think they did it before mixers? Pour the footer, all the way around. Then come back and pour stem wall in layers, all the way around. Use a concrete vibrator or tap the form with a heavy hammer. On a taller wall, I have used a 1"x2" to make a 1"-2" wide rough groove in the center of the top of poured wall to give the next layer more grip. Also wet before pouring the next layer if it is a sunny day....James


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## Harry Chickpea (Dec 19, 2008)

Hoover dam was done with multiple pours...

... it is still standing.


I would cut the make time by hiring about three day laborers to do the loading and grunt work, plus any odd jobs around. Saving money with a mixer, good. Saving aching muscles by hiring a couple guys and sitting back in a lounge chair with a lemonade, priceless.


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## farminghandyman (Mar 4, 2005)

do not know what kind of equipment you have to move the gravel and the cement, or how old you are, 

the only reason I would not use ready mix is if it is under one yard, or you can not get the truck in to the pour site.

I have mixed a lot of cement, over the years, I have a large mixer, (about 1/4 yard per batch). 

around here, the cost of the concrete, gravel/sand, vs ready mix is not that much different, I only save about $10 a yard, I do save on mileage, tho, but for four yards. 
and I still have to move (haul) the gravel and the cement, a yard of gravel is (if memory serves) 2200 pounds, and the 600 to 800 pounds of concrete, per yard, 

unless you have a good truck that is a lot of wear and tear on a pickup and trips,

and if you want addivities, which many times are not available to the DIY, 

to shovel a yard of gravel, carry and dump in 6 to 8 bags of 100 pound cement bags, and mix and then wheel barrow it to the placement, (I could do it at one time, not now, it is a lot of work,

usually just moving and working the concrete is enough work for me,

maybe your friends are better than mine, but to find help that will mix and pour concrete is not easy normally even when paying them,

IMO use the READY MIX. not worth your back or truck,


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## TnAndy (Sep 15, 2005)

farminghandyman said:


> IMO use the READY MIX. not worth your back or truck,


I'd agree.....concrete is around 4,000lbs per yard. Some of that is the water, but a whole lot of it is the cement, sand and gravel.

Did they do it in the olden days ? Sure.....because they had little choice. 

About a yard or so is my personal limit for hand mixing.


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## oldasrocks (Oct 27, 2006)

Cold seams would be the major problem. A place for water to get in, freeze and damage the footer.


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## watcher (Sep 4, 2006)

As several have pointed out you could do it but its probably not worth the effort. Some times it just makes sense to spend the money.


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## jwal10 (Jun 5, 2010)

I mix all my own concrete, Yes, nothing over 5 yards in the last 6 years in 1 pour. It saves at least half for me. Money in my pocket. I have mixed and poured foundations on 14 small cabins and cottages. Slabs for other projects, done in sections. Never had a problem with any. DSs' 24'x24' foundation 2 years ago. I have a 1/2 yard mixer, just 2 people, 1 mixing, both place it, 1 mix next batch and other person settling and working it....James


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## ihuntgsps (Mar 10, 2008)

I have mixed and poured thousands of yards of concrete. I have my own mixer I use for small jobs but for a 4 yard pour you will end up with a much better mix. 

Then add in what your time is worth, wear and tear on your body, and a poorer quality end product and see if the $100-200 you saved was really worth it.

Hire any help and it is a total no brainer to bring in the truck.

People did these projects by hand years back out of necessity not because it was a quality way of doing it.

If your in a cold/wet environment (make it way worse and say you have lots of clay in your soil) your cold joints better be top notch to survive all the freeze thaw cycles without problems.


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## ShotgunLuckey (Jan 26, 2015)

I drove a ready mix truck for over 8 years...footer mix is cheap, even with a light load charge and Saturday delivery charge. $90/yard, $100 light load and $50 Saturday delivery. Just make sure you are ready when the truck gets there or you may gat charged for overtime... And make sure you order a little extra, if you are short 1/2 yard, it could cost you $300 or more (1yd min, light load charge, Saturday charge...you great the idea)
4 yards is a lot to mix by hand, but it can be done


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## mreynolds (Jan 1, 2015)

pengyou said:


> Frugal homeowners' opinions are sometimes worth much more than a contractor's


So true. I have seen many frugal homeowners that had better sense than some contractors. I can say that without guilt being a contractor myself. These days in the trade it seems like its a crap shoot.


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## mreynolds (Jan 1, 2015)

pengyou said:


> I am drawing up plans to build a small cabin, that will ultimately have a room added on to become my home. The foundation needs 4 cubic yards of concrete. I have free access to a mixer that can do 1 cubic yard at a time.
> 
> Is it advisable to mix concrete by myself for this purpose? I have never done anything more than a wheelbarrow load of concrete.
> 
> ...


One thing that is nagging at me. Are you sure it is a 1 cubic yard mixer? If so it will have to be brought in on a trailer and set with a tractor. The ones at Lowes only hold about 4 or 5 cubic feet so it will only pour about 1/5 -1/6 of a yard. That means up to 24 mixes to get your 4 yards. 

I just poured 3 1/2 yards on Thursday and had to use a Bobcat skid steer to haul it in. A Bobcat will hold 1/3 of a yard full. Or mine will anyway. 

I would think cost would be a factor on the sacrete if that is what you are using to pour with. Here is a sacrete calculator so you can figure your own. 

http://www.quikrete.com/Calculator/Main.asp

Now you said 4 yards and a yard will cover 81 sq' (+/-) at 4" so I took the liberty to figure a 240' slab @ 4" and how many bags of #80 it would take. It came to 135 bags. So @ 3.99 a bag is 538.65 bucks. *You should be able to get it cheaper, do it with less labor and be finished earlier to plant the garden later if you call in a concrete truck. *3 to 4 yards is usually the minimum charge they will bring anyway so no extra costs there. Also you may could even get 5000 psi for not much of an upcharge. 3000 is the minimum for code.

I would like to say that I am not a concrete man but I have done my fair share over the years. Both ways. Last years we had some sacrete donated to our VFD and we poured a slab for a diesel tank in August and it took us almost all day. But even though it was free concrete we decided to never do that again.


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## mreynolds (Jan 1, 2015)

ihuntgsps said:


> I have mixed and poured thousands of yards of concrete. I have my own mixer I use for small jobs but for a 4 yard pour you will end up with a much better mix.
> 
> Then add in what your time is worth, wear and tear on your body, and a poorer quality end product and see if the $100-200 you saved was really worth it.
> 
> ...


Your post reminded me of my neighbor back when I was a kid. He passed on many years ago but he was a concrete man and like you he probably poured thousands of yards in his lifetime. I helped him pour his add-on and retaining walls. He would buy the sand, Portland and gravel and mix his own. For the life of me, I cant remember the mix he used. I did the mixing but under his guidance. It was 35 years ago but I feel like I should remember it. He always said that concrete trucks were for these new guys who didn't know how to mix concrete.


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## jwal10 (Jun 5, 2010)

I just got done helping pour a new foundation for an old house, 24'x32'. House was jacked up and we hand dug a foot of dirt out. Dug the footer and formed with 2"x8"s. We poured the footer first, put in the keyway, then came back and put up the forms for the stem walls. The owner of the house hauled the concrete from the batch plant at the rental place with his pickup, from town, 26 miles away, 1 1/4 yards at a time in their little buggies. The 3 of us then placed the concrete with wheelbarrows and shovels. The 2 of us vibrated it and put in the keyways while he went for the next load. When we pulled the forms, it looks as good as the big guys' jobs. We kept the top of each pour wet and worked in the next lift. It can be done. Actually the breaks gave us time to make sure everything was "perfect"....James


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## chuckhole (Mar 2, 2006)

MReynolds, the mix is 2-1/2 to 3 parts aggregate, 2-1/2 to 2 parts sand and 1 part Portland Cement. Mix the dry together and then add 1 to 1-1/2 parts water.

The last slab I mixed with my 5 cu yd mixer was approx. 2 cu yds and I will never do one that big again without help or a delivery.

I used buckets - 5 gal each for the sand and gravel, 2 gal for the Portland Cement and water. It seemed like I was hauling, mixing and pouring for ever, and it was. I was able to do about 5-6 mixes per hour and it is not easy to trowel and screed by yourself along with keeping up with the mixes.

The good news is that I managed to keep pouring next to wet concrete each time so after 10 years, the building is still sound and the slab has no issues.

So, all of my mistakes in that endeavor brings up a few questions. Should I have done this in July in the south (Texas)? Absolutely not. I am lucky I was able to keep a wet pour going.

Should I have had help? Definitely. I was 45 yrs old 10 years ago when I did this. It took me a week to recover from the soar muscles.

I am just an avid DIYer like so many on this site and brains don't always attend the same parties as I do.......so it is what it is.

In short, can you do what you want to do? Yes. But remember, there are other things to consider, like the proper tools to get the job done. You will need a 4' bull float with a rocker handle and extensions, a placer (come along), maybe a Fresno, some hand trowels, edger and some rubber boots. 

If this is a one time thing then spending $400 on tools can easily justify the price of delivery truck and some paid help.


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## mreynolds (Jan 1, 2015)

chuckhole said:


> MReynolds, the mix is 2-1/2 to 3 parts aggregate, 2-1/2 to 2 parts sand and 1 part Portland Cement. Mix the dry together and then add 1 to 1-1/2 parts water.
> 
> The last slab I mixed with my 5 cu yd mixer was approx. 2 cu yds and I will never do one that big again without help or a delivery.
> 
> ...



That mix sounds about right. And when your in your forties you still think things are a piece of cake. When at times in your fifties.


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## Steve_S (Feb 25, 2015)

Hand mixed & poured 48 bags of Sakrete last fall for my pump house slab, in a wheelbarrow. I'm fairly fit and over the 50 yr mark... would I do that again ? *NOPE !* Of course I did it all in one day, made a few minor mistakes but it turned out very well and no problems... Sore back, aching arms, tired legs and a few pounds lost through sweat but I survived it... 

My next probable concrete job, a 20'x20' Frost Protected Slab Foundation would requiring 7.5 yards, or in pre-mix bags: 667 40# Bags, 445 60# Bags or 334 80# Bags. I ache just thinking of it so Mobile Site Mix is the option I am looking at for it... We have a local company that mixes the concrete on-site to spec and only charges for what they mix. This prevents overages & underages (and saves $). 

Check around and maybe you can find a local company that does similar onsite mixing. Here is the company I am looking to in my area, hopefully this info will help you find one local to you. Tom Mix Mobile Concrete, Pembroke Ontario Canada


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## texican (Oct 4, 2003)

Was at Home Depot today.... they had sakrete pallets out, and the best price was 3.57/80lb bag.... which, if I recall, each bag has about .6 cubic feet. At that price, the raw materials cost ~160$, plus tax, and all of the unloading (front end loaders are great, move the entire pallet at once), loading and mixing. Meanwhile, a yard of already mixed concrete (last I checked) was around 110$/yard.
Like others mentioned, unless you simply can't get a truck there, what's the point? Operational security.....not wanting strangers to know what you have? 

I've got two mixers....but would dread pouring 4 yards in a day...


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