Mixing Your Own Concrete

[Bull]

What is the largest area that you have mixed and poured your own concrete in?

I'd like to put a new floor in an old barn, and just am not going to have the budget to have a truck come in and have guys do the prep and pour. That leaves me thinking about busting up the old slab by hand (which is fun for me) and pouring on my own. I would only do this if I heard from others that a lasting result can be achieved i.e. wont crack and crumble into dust in two years.

I reckon, I could do each bay of the three bay barn in sections.

But, I might be full of ****, so let me know if it's just a bad idea.

 

[Lkdelta]

What about calling the truck company...and you and some friends do the prep........ and pour when the truck backs in?

We did a sidewalk about 30" by 15 ft with a wheelbarrow and bags of portland and some stone
Kinda hard to keep consistancy mixing bags, sand and stone, a wheelbarrow at a time

 

[ishiboo]

What is the largest area that you have mixed and poured your own concrete in?

I'd like to put a new floor in an old barn, and just am not going to have the budget to have a truck come in and have guys do the prep and pour. That leaves me thinking about busting up the old slab by hand (which is fun for me) and pouring on my own. I would only do this if I heard from others that a lasting result can be achieved i.e. wont crack and crumble into dust in two years.

I recon, I could do each bay of the three bay barn in sections.

But, I might be full of ****, so let me know if it's just a bad idea.

I've been looking into this same kind of question.

It's cheaper to do all the prep and buy the concrete premixed and delivered.

For example, a 10x20' slab of 4" concrete would be a minimum of 2.5-3 yards. Here concrete is about $80/yard (closer to $70), or $240 for the concrete.

That same slab would take 223 40-pound bags, or 112 80-pound bags. That's a lot of mixing, and unless you find some REALLY cheap bags, it'll still come out cheaper to have the truck come. That's also a LOT of mixing to do, and a LOT of concrete to move around. Plus you know it should be top-notch stuff, correctly mixed, when it comes.

Use either rebar or wire mesh and it will hold up quite well

 

[OccupantRJ]

Bull, what I have been doing is prepping the pour myself, then hiring grunt Helpers from my regular workplace to provide the labor. A co-worker of mine does a great job finishing concrete by hand, and I hire him to do that part of it, making him the foreman, and me the project manager. He has poured lots of driveways, but the largest pad he has poured has been my storage shed, which was 18 by 20. He also poured my shop expansion, which was 10 by 26, and an 8 by 20. I don't think you might want to tackle the bag by bag method.

 

[930dreamer]

We did a kennel and a small basketball court. Did all the prep and forms and trailered back the reddy mixed concrete. I think they held two yards. It's kind of a pain that you can't mix the concrete in the trailer before you pour. It took a couple of trips.

Bull, section it off and pour as you can. Make it at least 4" thick. Offer to feed a crew of friends and go after it.

 

[walrus]

Bull
How big are the sections? I wouldn't do more than maybe 6 by 6, its alot of work. I would never use Sakrete or Quikcrete for it. While a truck of concrete is expensive its a lot quicker and the quality control is a lot better.

 

[Busted_Knuckles]

Ive mixed and poured some plumbing ditches in some commercial restaurant re-models, its way more work than you can imagine. Those 80 bags, don't make near as much concrete as you hope for.

The ditches where just cuts in the concrete floor, maybe 16" deep with pipes and about 24" wide by maybe 25' long. I think I did two by hand, and that was more than enough of a negative experience to get me to call a truck.

If you want, buy 5 bags, mix it and see how far it does not go. Its a PIA !

Good luck ! BK.

 

[toolmiser]

I think if you google concrete calculations, or go to a major brand's website, you will find how many bags it will take to do a specific job. If you want to wait till you get the prep work done you might change your mind. I did a garage addition where my wife and I did the prep and just had professionals do the pour. I didn't have the "staff", and wanted a decent result.

 

[jmh21586]

quickcree for an example:


4" thick.
10 sqft = 8 60# bags.

10 sqft = 6 80# bags
add 50% for 6" floor.


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

 

[Busted_Knuckles]

Ive got a good sized concrete "mixer", its a nice well built commercial model from the 80s, I only use it for making mortar for "grape vining" and re-pointing. That would make your task much easier, but even with that on hand, it would still call a truck.

 

[jmh21586]

There's really no way to mix that much and get it poured before you end up with cold joints.

 

[holdover]

you can probably buy it pre mixed cheaper than you can mix it yourself, and it will be a better job, and take a few hours total rather than a long time, a yard of cement is alot of cement hand mixing, i speak from experience. If you have never done this before research how it is done, maybe go somewhere that is doing a pour and watch. You can rent or buy the tools to do the job, float etc. If the truck can get to where you are doing the work , most of the hard work will be done by the operator putting the concrete where it needs to be, using chutes etc. I have a cement finisher that I use that charges .50 sq foot and he does the pour and machine finishing, I lay up the perimiter boards and level everything out with my laser leveler, for a small job a line level will work fine. Check with the transit mix company what their minium load is, usually 2-4 yds. good luck

 

[Printer Mike]

In 2005, after 30+ years of erosion to the footing of the 100' cinder block seawall at the lake place, it was time to fix it or lose it. The lake is let down every five years for approx. 30 days.

With a tight budget, and a lot of free time it made sense to 'DIY' it. I bought a cheap concrete mixer and many, many 80 and 40# bags of concretre mix(probably at least 10,000 lbs) Spent a whole month digging new footers, forming and pouring. Tuned out great, and just this past year, went back and finished a 15' section that was missed in 2005.

It would have been great to dig everything, form everything, and pour from a truck, but the way it was done, I was able to rest every few hours and figure out stuff as I went.

 

[dtt454]

i did a 13x40 x4" padio myself, after calculating bags it was like 2/3 the price to call a truck, however a truck wouldnt fit where i needed it. where i live the local rental place sells concrete, they mix it and put it in a little trailer, as long as your back within 4 hours they dont charge for use of the trailer. i think there big trailer was something like 1 1/4 yard and it was only a couple miles from me, so i had a helper drive my pickup back and forth 5 times while i stayed and worked it in and finished it.
still ended up costing almost 900 if i remember right, but was the cheapest way i came up with. that was with renting the finishing tools too.

 

[Gary S]

I grew up out in the country where there was no option to call in a cement truck. Everybody mixed their own concrete in a small electric cement mixer. My Dad and I alone mixed the cement for his 24x28 garage in one day, and with more people we mixed much larger jobs.

Anybody who says it can't be done just doesn't know how to do it. I see a lot of that in today's world.

 

[walrus]

Anybody who says it can't be done just doesn't know how to do it. I see a lot of that in today's world.

Of course it can be done, that doesn't make it, cheaper, easier, better or a more efficient use of time. Nor does it make it a better product when done

 

[Oldtymeflyr]

You will have a much better product if you buy ready mix.

Do the prep, install the rebar then do a pour with friends.

Also, tell the truck operator that you are going to tip him $40-$60. You now have your expert.

Regardless, do not over work the surface. Be careful of steel trowels, better to use aluminum or wood. Have some 2x3x3/4 plywood panels for working the concrete.

Be patient, do not go after it too fast, wait. Did I say wait, wait. #1 mistake.

Rick

 

[green.bubbly]

You may want to look into the U-Cart rental. You can get concrete pre-mixed and haul it home to pour in a mini-concrete truck. It is a little more than purchasing from a concrete supplier but it is a lot less work.

I am not sure how big of an area you are doing. One cubic yard will probably run a around $120.00.

 

[tatra]

also keep in mind at the end of the day you will have tailings from rinsing out the drum............concrete truck is responsible for taking it back or is on the hook if caught dumping illegally..........used to mix concrete for 7 ft by 6 in. piers for a precast step installing comapny...........doing a cuople or 4 was ok but if i ever had to do more than six at one site i was going to get them to spring for the redimix............and as said, 80 lb bags of cement are sucky to manhandle............not to mention that concrete gravel can and does get mixed up for other products by those that sell and deliver..........along with contaminated dump boxes used for soil........

 

[OccupantRJ]

Due to physical constraints of my property, when we did my pours, I rented a powered "Georgia buggy" to truck the concrete from my driveway entrance through a gate to the pour site, a distance of 200 feet. It cost a little over $100, and was worth every penny of it, as I could drive right up to the sides of the form and put it very close to where it needed to be. The unit has a hopper that works like a dump truck.

 

[rsanter]

about a 3' by 3' section that was 4'' thick and it was a *****

dont even think about it. at minimum you will need to order a truck load to come in and maybe you could do it yourself from there. but to try to do it from bags, your nuts

bob

 

[jmh21586]

Think about it and do the math, and I think you'll quickly realize what a pain in the *** it would be to mix it yourself. Getting the mixer, buying the concrete, hauling it home, yada,yada.

I don't know if the savings would justify it.

I'd maybe talk to the redimix plant and see if your order could be tacked onto someone elses to maybe get a better deal. You'd have to be at the whim of someone elses project and just be ready at a days notice, but it might be worth the try. Got any neighbors looking to do a little pour? Never know.

 

[James E]

If it's a barn floor and you don't care if it looks very good, you can offer the floor to the local concrete guys as a place to dump extra concrete after they deliver to jobs. The guy I worked for back in the eighties had about a quarter acre behind his gas station done that way. It looked pretty crappy but it was solid and free.

Other than that, I know from experience that you CAN do it with a small mixer and a shovel (my boss was a cheap ******* that would work us to death to save a few bucks), but I doubt that you will WANT to do it once you become aware of how much work it's gonna be.

Grading, forming and placing rebar or other wire is not rocket science. You can do that yourself and save all of the labor cost--then have the concrete co deliver and work it on your own with a couple buddys to help work the screed board with you. Rent a couple floats and an edger and you're on your way.

 

[wssix99]

You may want to look into the U-Cart rental. You can get concrete pre-mixed and haul it home to pour in a mini-concrete truck. It is a little more than purchasing from a concrete supplier but it is a lot less work.

I am not sure how big of an area you are doing. One cubic yard will probably run a around $120.00.

This is really interesting. This is what I was thinking as a middle-of-the-road option. You can rent these trailerable mixers from any good tool rental place and have the proper sand and gravel delivered for your mix. Using bulk gravel and sand with standard 94 lb. bags of raw portland cement will make things go a lot better (and less expensive) than buying 60 lb. bags of pre-mixed quickcrete.

I've done slabs of Bull's size using this method but it took a bunch of strong people, a few shovels/wheelbarrows, and one person with the right mix design. I'd guess this could be pulled off with a group of 6 guys who will do hard weekend work for beer.

 

[Racecarl]

I hired the redi-mix truck for pouring my foundation walls. That pour was nearly 15 yards. My 'superintendent' was a PE friend that worked for the highway department. Two other buddies and myself were the 'grunts' and the walls came out OK considering I had never built forms before. The same buddies helped me with the driveway almost a year later.

I hired the 24 X 30 floor poured and finished. I was busy and I wanted the floor finished with a power trowel. I did all the prep work came home from work one day and the floor was poured and finished. They came back the next day to put in the expansion cuts.

This left me with the sidewalks and a small patio. It would not be possible to form and pour what a needed done all in one shot. My grandpa had a cement mixer from the 1950's that he used to make lots of concrete structures, so I used it. I would form up sections that I could do in an evening and eventually I got all the sidewalks and patio done. I ended up pouring about 6 yards of concrete this way. I had the redi-mix place bring me 6 yards of aggregate and I mixed the concrete. It took 13 heaping shovels of aggregate and 3 smaller shovels of cement per batch. My 15 year old son and I would mix and place the concrete, which was good for him as he learned a little bit about how concrete works. One day my Dad came up and mixed for me, which really accelerated the process. It was more work with the small mixer, but I did save $40/ yard.

The truck is easier (labor wise) and faster, but is not always practical, at least in my case.

 

[RPH]

Think about your labor and put a price to it, it does have value. The ware and tear on the bones out way the savings. Concrete work is hard and heavy. I does have serous time constraints on it. Use this site and look at the number of bags used to do the area and remember the stone in it will be small compared to the truck.
http://m.concretenetwork.com/calculator/
Handy site for estimating.

 

[brownbagg]

bagged mix is a 1500 mix, it would be almost double to do it with bags, but if you have to, do it right with portland cement, a pile of gravel and a pile of sand. bag mix is for fence post

 

[ddawg16]

I did a 2'x20' section behind my house....took about 16 bags or so....

Lets see....there is the loading at HD....
Unloading at the house....with luck you can back up to the spot to be poured.
Lift each bag...cut...empty....mix in water...
Pour
Spread

Repeat.....16 times or more....

First couple of bags are not bad....Come the 15th bag.....all of you is hurting.....

Never again....unless it's less than half a yard....

A place about 1/2 mile from me has portable totes...you back your truck up to it....hook up...back up to the mixer....they mix and dump what ever amount you want. Runs about $130 yard....If I need less than 5 yards.....it's cheaper....after that, a cement truck is cheaper.

 

[PCO6]

I poured a 10' x 15' floor for my utility shed about 15 yrs. ago. I had the sand and gravel dropped off at my house and picked up bags of cement at Home Depot. I used the "family cement mixer". I did it in 3 sections of 5' x 10'. I did it by myself and found I really had to keep moving ... it's a good work out! It's a lot of work but I found it satisfying. The floor has held up well ... better than the shed!

 

[Stephenw]

I did an 8 x 10 slab with a mixer attachment on a Bobcat. I just had to dump the bags in the mixer and add the water. The Bobcat did the work of moving the cement and dumping it into the form. The Bobcat mixer can hold a bigger batch than the typical small mixer too.

It was still hard work and I was sore for days.

I think I'd call in a truck for anything more than fence posts.

 

[UncleJoe]

Worked my way through college doing concrete. Don't even think about mixing it yourself. Breaking up the existing floor and setting rebar is the easy part. Do all the prep and have a truck deliver the mix. If you have never done concrete it is no too hard but a big job like a shop or garage floor is not the place to learn all by yourself.

 

[NUTTSGT]

I've used bags, mixed my own and had the truck bring it. The truck by far is the easiest and best mixture but it's not always the right option for the job.

When I did the sidewalks around the house, I mixed my own. 1 part Portland cement, 3 parts stone (#8) and 3 parts concrete sand. It was way better than the remixed in the bag concrete. For a small job, I'd have no problem mixing my own but something like an apron on the garage, I'm calling the truck.

truck for the floor.

Mixed the columns in the mixer myself. . . neighbor's electric mixer, thanks Bob

called the truck again.

 

[tdkkart]

30+ years ago when I was 14 or 15 my Dad got tired of me having stuff torn apart in his shop so we did one up for me in an essentially empty section of our barn. The are was 16-18ft wide, easily fit 2 cars side by side, and 2+ cars long, I'm guessing 40ft, with an 8ft ceiling.

First order of business was to dig out the dried sheep **** that was at least 15 years old, with the tractor and loader. Dad says "dig it down till you find black dirt." Little did we know that apparently that end of the barn, which was built on a bit of a hill, had never been back-filled when the stone foundation was built. The front of the room had about 18" of sheep ****, the rear nearly 4ft!!! Thank God for the tractor.

Backfilled and packed with dirt and sand and then formed it up. We ran 8ft wide pour down the center and then had 2 4+ft runs down each side.

Pile of sand, pile of gravel, a large stack of bag cement, electric mixer, a wheel barrow and one LONG day later we had the center pour done. Mixed 3-4 sorta wet mixers full, screed it off, mix some more, broom the top as it firmed up. Over the next few days we did the 2 side runs which were gravy compared to the first.
The floor turned out great, and was something to be proud of.

I did a "driver restore"' of my first car, a '68 cougar in there. Brought a Fiat X1/9 back from the dead after an engine compartment fire, several motorcycles of mine and friends, and many friends cars made their way in and out over about 3 years.

June 1984, a year after I graduated highschool, a tornado came through and knock the barn flat. A D9 Cat was brought in and un-ceremoniously shoved all our hard work into a hole...............

 

[mad57]

My father just told me of a truck that mixes the (crete ) sand and stone and crete/water on the spot and only what you need for the exact job your doing, that would be best for you go by your budget and get that amount done even if its 10x10 at a time. than you just have to trowel it out yourself.

 

[tatra]

mixed on the spot may not be the quality one is looking for as the batch mix can have additives that the spot mixer may not have..........fine for sidewalks and such but for supporting cars, would research the specs before going that route.........

 

[MoonRise]

Get a redi-mix truck for a slab worth of concrete. IMHO.

Do the form work and prep work yourself. That part of the job has no 'cure-time' time constraints, because remember,

Concrete waits for no one.

Let me repeat that, once the water is added to the mix, the clock is ticking and the concrete is starting to 'cure' or set-up. No time-outs available.

So for the actual pour, make sure you have more than enough manpower to spread and move and screed and float and trowel the concrete as needed.

Because, Concrete waits for no one.

After the slab is all done, THEN you can sit back and have lunch/dinner/beer or all of the above.

Because , Concrete waits for no one.

Notice a repeating theme here?

A 'little' 10'x20'x4" slab is 2.7 yd^3 of concrete, or via the handy-dandy ConcreteNetwork site, 112 80# bags of concrete. That's 8960 pounds of DRY concrete that you have to pick up and move. That wil be darn close to 10,000 pounds of WET concrete once you add the ~275 pounds of water per cubic yard of concrete.

And I would not relish mixing and moving 10,000 pounds of concrete by hand and wheelbarrow. Although looking back, I think I actually DID do that moving part for a redi-mix walkway (the truck chute couldn't reach far enough so we had to wheelbarrow most of it to the 'far' end of the walkway).

Break up the old slab, dig it out as needed, fill with gravel underneath as needed, form it as needed, put in the vapor barrier as needed, put in the rebar/mesh as needed, all those steps have no ticking timeclock on them.

But once the water is added to the concrete mix, the clock is ticking and the concrete will set up whether you are ready or not. So, you HAVE to be ready to spread and pour and screed and float the concrete.

Because, Concrete waits for no one.

IMHO.

 

[Falcon67]

Concrete waits for no one.

Let me repeat that, once the water is added to the mix, the clock is ticking and the concrete is starting to 'cure' or set-up. No time-outs available.

What he said X100. If it's big, hire a crew. If you get some experienced guy friends, that's OK too. On a big slab amateurs = potential problem. Concrete does not necessarily go where you want, it has to be pushed and prodded. There is also tamping to remove air pockets, working the edge of the forms with a hammer to drive out air and get the mix up against the forms, etc.

Note - check with the concrete company first. Around here, they do not provide crews. And the driver delivers - that it, no help what so ever. They are truck drivers, not concrete experts. Tip your crew, not the driver. The driver doesn't know where you want it placed and will have to be directed by someone on the crew. If the boom can't reach where you need the mix, then you best have people pulling the **** out of it to move it where it needs to be. You'll also need a washout area for the truck - they clean the dumper and the boom on the spot.

They just poured a 2800 ish sq foot house slab next door. 90 yards of concrete. Three hours of delivery and they works constantly, 9 or 10 guys. The first truck arrived at 7:30am, the foreman signed for the delivery at 10:30 and the forms were off, slab power trowled and crew gone by 3 PM. That was Friday, it had walls up on it by Monday evening.

I'm planning for a 24 x 4x' shop. After watching the dance on that slab, I'm 100% sure I can do everything except manage the pour. It'll take 3-4 people just for a rectangle with no brick ledge and a couple of door steps.

Note the guy floating while the pour goes on - it really goes that quick.

 

[slimpickins]

The area you can reasonably do depends on the size of the crew you have helping you. You have to do it in sections according to the speed you can mix, place and finish the concrete. This even applies to ready mix.

Then you have to develop a system to divide the job into sections - 4 x 4, 6 x 6 or whatever your crew can mix and place in about an hour or two. Any longer and it starts to set up too much to finish well.

For good results, your sections need to have rebar through the sections, and the section breaks should not be too smooth as it will create a shear line. Think about adding key-ways in your section forms - blocks of wood that create cavities for the next section to fill - and you have to use a bonding agent between sections (I use watered down Weld Bond glue which makes a quite effective bonding agent, or you buy the bonding agent for 203 times the price.

You can get just as good a result as ready mix ... IF... you're careful about consistency of the mix (ratios, water content, etc.) and you get good material (put a shovel of aggregate in water and see if you've got any iron content that will rust through to the surface. (this even happens with ready mix).

It's back breaking work to mix concrete by hand (wheelbarrow) or even with a mixer - you still have to shovel the mix into the machine. Unless its really small (3 or 4 wheelbarrows) I won't even consider hand mixing. You are probably working for less than minimum wage for what you save mixing your own.

 

[NUTTSGT]

BTW Bull, the sidewalks I did myself were poured in sections, day by day. Along the house garage, those were 4' x 4' sections. The sidewalk to the front porch, those sections were 4' x 8'. I did these myself and it about killed me, "because, Concrete waits for no one"

 

[Charles (in GA)]

Anybody who says it can't be done just doesn't know how to do it. I see a lot of that in today's world.

Of course it can be done, that doesn't make it, cheaper, easier, better or a more efficient use of time. Nor does it make it a better product when done

I agree 100%. Saying that something can be done, doesn't make it the best or most desirable way to do it.

You will never get the nice smooth finish most people want on an interior concrete floor, it just isn't possible when you are piecemealing it with concrete from a mixer being wheelbarrowed to the forms and dumped, the first is almost set when the last is just being poured and you don't have time to properly finish it.

A friend of mine decided to build a 12x16 gambrel roof building in his back yard. He dug and formed the slab area, and found that due to slope, septic tank and fences, there was no way to get a truck close to it, so he ordered in a huge load of quickcrete in bags and rented a gas mixer. We quickly discovered the rental place saves the **** mixers for individuals. The good ones go to contractors as they are repeat business. Individuals are not repeat business, so the rental place doesn't care. He got the mixer that fouled the spark plug about twice an hour. Well, Rick and his wife started on the project one Sunday morning and called me, "HELP" and I raced up to their house and we spent the day mixing and pouring the slab. He would load the mixer, his wife would dump in the water, and mind the mixer while he wheel barrowed it to the forms, where I spread and leveled it and tried to finish it, and set anchor bolts (he had failed to make nail on pieces to hold the anchor bolts so I had to freehand set them, only one wound up out of place so I didn't do too bad).

Rick, being the **** person he is, decided the slab needed to be 6" thick to support his small Kubota tractor, so this added to the work. We got done, and the building built and was as perfect and sealed up as any ever built, but I'll never again do that!

Being the too nice, never complaining, never standing his ground, person he is, I was never able to get Rick to complain about the mixer to the rental place. He told them he had "some problems" with the plug fouling. In reality, he ended up taking the plug from his mower and swapping the two plugs in the mixer, cleaning the fouled one, changing them quite a few times during the day. We probably lost over an hour to plug changes and cleaning plugs, but he would not demand a partial refund or otherwise complain...............

Charles