DIY concrete expertise/questions

[JHZR2]

I have interest in doing a DIY slab. Figure 60SF +/-.

I think it’s too small for a truck, and it seems a good candidate for DIY. I’ve done small jobs where Immix in a bucket, nothing this big.

Thing is, 80# bags aren’t very much. And the rentable mixers that are 3.5-4 cu ft are only good for about 2 80# bags. Quickrete calculator says 34 bags…

Is this an amount, and fillable/mixable/pourable at a tempo that is practical for 2-3 people?

What is practical?

How big of a pour have you done with bags and a mixer? Has it come out ok?

I could do fractions at a time, and then just naturally have the expansion joints present from the partition between pours, fwiw.

Thanks!

 

[SC Maintenance]

60 square feet at 4 inches thick is only 20 cubic feet of material? Even the small mixers do a couple or three cubic feet a mix don't they? It shouldn't be a problem that I can see. You need to build proper forms and reinforcement, and rough trowel as you go.

 

[ctechbob]

I've recently had something brought to my attention by my mom who is looking to do a small slab.

I can't vouch for the procedure, but I know I've used this method for fenceposts before and it has worked just fine. The logical part of my brain thinks that for something non-structural, it would be ok. Something like a small DIY slab, not saying I would consider it for a house floor or garage or anything. But that's about all the research I've done so far.

 

[simple_gifts]

OT: no chance of piggybacking on someone else's larger job or taking leftovers.

I've never done that myself, but seem to recall someone mentioning it to me years ago.

 

[tblt44]

Dry pour
Na I believe it needs mixed well to have strength

 

[92saturnsl2]

I have interest in doing a DIY slab. Figure 60SF +/-.

I think it’s too small for a truck, and it seems a good candidate for DIY. I’ve done small jobs where Immix in a bucket, nothing this big.

Thing is, 80# bags aren’t very much. And the rentable mixers that are 3.5-4 cu ft are only good for about 2 80# bags. Quickrete calculator says 34 bags…

Is this an amount, and fillable/mixable/pourable at a tempo that is practical for 2-3 people?

What is practical?

How big of a pour have you done with bags and a mixer? Has it come out ok?

I could do fractions at a time, and then just naturally have the expansion joints present from the partition between pours, fwiw.

Thanks!

My wife and I did a DIY concrete apron in front of the attached garage. Home builder left it like a curb and I got tired of watching my wife have to get 5mph head starts to get in the garage.

13'8" x 4' was the dimension. I believe we used about 35 bags; approx. half were 60# bags, the other 80#. We aimed for at least 4" depth throughout, but at the end, started running out of concrete and had to taper it. Actually worked out well because it's just a spot for people to step off, and met the ground level perfectly.

Our forms were rudimentary, just something to hold the concrete in. We used a float to move the concrete around to the approximate slope, then followed up with a trowel to smooth it out as best we could. Not perfectly flat by any means and there are a few trowel marks, but it sure does the job and I'm happy with it.

I did it mixing in a wheelbarrow and going as fast as I could while the wife spread it. It's not a task for the faint of heart and I was super glad when my FIL stopped over toward the end and had an extra hand for finishing. I finished cutting the control joint (to match the slab) the next morning and like clockwork, the concrete cracked right there (like it's supposed to) and 6 months later I have no cracks elsewhere.

 

[Kansas_Ron]

Do yourself a favor and have it delivered by a ready mix truck. You will have a better product. You can have it placed and finished in a fraction of the time you would use buying the mix, handling the mix into a truck, off the truck, into the mixer etc. The most difficult part will be wheelbarrowing it to your location. It appears you will need about 0.75 of a yard. Some companies will mix the concrete on site. I am sure there is a delivery rate flat fee and a minimum of a yard or something. But seriously, spend the extra cash and have the concrete delivered, get yourself a nice 2 wheel, wheelbarrow and have the finishing tools needed and have 1 or 2 good friends to assist. Life is too short to mix 34 bags.

 

[earlyre]

OT: no chance of piggybacking on someone else's larger job or taking leftovers.

I've never done that myself, but seem to recall someone mentioning it to me years ago.

My uncle wanted a small "patio" beside his deck... basically a small slab big enough to put his grill and maybe a small table on... like 6x4 ft.. I think...(edit..google maps measuremets put it around 9x9, maybe 10x10)
called a local concrete guy, who came out and looked it over, "too small for a full job, but if we get a nearby job, we might be able to add this to it..."

a few weeks later he gets a call, that they will be able to pour it in a couple days. (his subdivision is still growing, his was the first house in the second phase, now in the 4th phase....)

piggy backing definitely happens/works...

 

[bbhero]

And I could be wrong here ….

But the subgrade below that concrete should be done well too before pouring concrete. Which could mean digger deeper by 4-8 inches deeper and filling it with crush and run gravel and tamping it down extremely well too.

I could be wrong here….

But I remember my age father building a large salt treated deck and he dug the hole for the support post really quite deep… I think 30 inches deep. Filled them with small pebble gravel quick concrete. Then he placed pre formed concrete pads on top of that. Then salt treated 6 by 6 posts. And he used a LOT of them to support that salt treated porch. It was amazingly strong and it never shifted or got out of shape. You could have put a loaded dump truck on that porch.

Seeing that and other road projects in my life I have seen that the sub grade being prepped right makes the structure above it last like it should and be structurally sound for a very, very long time.

 

[doitmyself]

I did this once: local concrete facility has "U-cart" system for up to 1 yard. Google "u cart concrete". Your cake and eat it too answer.

U-Cart Concrete Rentals | Southwest Michigan

Rent a concrete U-cart at Peterman Concrete that can haul up to one cubic yard of concrete. Call for concrete pricing. Free instant phone estimates.

www.petermanconcrete.com

U Rent It | Redi Mix Concrete | | (616) 538-8080

The quick and easy way to get your concrete job done. Great for small residential jobs. U Rent It Concrete can be made from 1/4 yard to 1 full yard. We mix it, and you haul it. Pouring concrete for over 50 years.

www.urentit.net

U-Cart Premixed Concrete Trailer Rental in Portland, OR

Use our concrete trailer rental service to take our premixed concrete to your job site. We offer several strengths with pickup and short-load delivery options.

johnsonconcreteproductsinc.com

Places like Sunbelt have 9 cu. ft. mixer rental also. https://www.sunbeltrentals.com/equi...-cu-ft-gas-concrete-mixer-tow-behind/0150150/

 

[JHZR2]

Do yourself a favor and have it delivered by a ready mix truck. You will have a better product. You can have it placed and finished in a fraction of the time you would use buying the mix, handling the mix into a truck, off the truck, into the mixer etc. The most difficult part will be wheelbarrowing it to your location. It appears you will need about 0.75 of a yard. Some companies will mix the concrete on site. I am sure there is a delivery rate flat fee and a minimum of a yard or something. But seriously, spend the extra cash and have the concrete delivered, get yourself a nice 2 wheel, wheelbarrow and have the finishing tools needed and have 1 or 2 good friends to assist. Life is too short to mix 34 bags.

That’s kind of the angle I was looking for. I get it that lugging 34 x 80lb bags is a lot of lifting, but we do more lugging the kids around or going to the gym. But what I don’t understand is how fast/convenient it is to keep mixing two bags at a time, and what the practical working time is.

 

[Kansas_Ron]

That’s kind of the angle I was looking for. I get it that lugging 34 x 80lb bags is a lot of lifting, but we do more lugging the kids around or going to the gym. But what I don’t understand is how fast/convenient it is to keep mixing two bags at a time, and what the practical working time is.

There is nothing fast about 2 bags at a time. The first 2 bags you mixed will be curing by the time you get to the last 2 bags. You want concrete to be placed and finished at about the same time.

 

[Drew7a]

Some concrete tips:

Always keep the water/cement ratio as low as possible for better strength.

Try and keep the concrete wet while curing you will add more strength to the concrete. This can be done several ways. I have used drip lines, sprinklers, wet burlap bags, covered with plastic. Sealers, but the idea is keep concrete hydrated for proper curing.

Do not pour during extremely high temperatures, you do not want to overheat the concrete.

Add 6-8% air entrainment if concrete will be exposed to freezing

If you need a higher slump, use a plasticizer but never more water.

 

[Vil_Riker]

Definitely doable DIY but as others have said, there are potential downsides. I have done this years ago without a mixing machine, with shovel on the ground, and it's still there 30 years later. But the lines where different batches were poured are visible.

Prep is very important as well.

 

[PimTac]

We did a driveway of around 25 feet long by 12 feet wide. It was done in three sections. Each section was done on separate days. The concrete was mixed by hand on the ground. This is really old style.

It has held up very well despite several earthquakes including a 7.2. No cracks.

We also did our sidewalks in the same fashion. I would estimate around 120 feet of sidewalk was poured in the same manner. Those also held up well except for one section that was damaged in the big quake. We replaced that.

This is not to dismiss what has been suggested but it is one example that other ways can work.

 

[dnewton3]

I have poured some front porches, front walks, garage aprons and even a garage floor in my youth. Here are my thoughts:

- VOLUME: you'll need less than 1 cubic yard; that's not much. Most concrete suppliers will deliver that, but typically have a minimum charge of 3 or 4 cu yards; so you'd be wasting some money. Still, having to mix that much by hand is VERY hard and tedious. You'll get a much better mix buying from a supply source rather than mixing at home. It may seem like a waste of money, but I prefer premixed delivery; it goes SO much faster and the product is much more homogenous. You might even call around and see if there are some other projects nearby that are also looking for small quantities; the delivery might be able to be "shared" across a few neighbors, etc. It's not very cost effective for a company to deliver 1 cu yard, but if you can get your order tagged onto another of 5 yards or so, then maybe you can bring the cost average down.

- USE: what's this for? decorative? load bearing? These things make a difference in your decision. If load bearing, you might want to consider adding fibers to the mix (strengthens the mix). This is easily done by the supply source if you choose to buy and have delivered.

- TOOLS: you'll want to rent/borrow a hand bull-float and finishing tools, especially if you want to make sure it's presentable to your friends.

- FRAMING: take your time and do good prep work. Make sure to use straight and level boards.

- GRADE BASE: put at least as much base into the project as the amount of thickness you expect to pour. 4" of concrete would call for 4" of gravel base; tamp it down well also

- YT Vids: believe it or not, there are some good YT videos out there that show how to DIY this kind of stuff.

 

[SC Maintenance]

There is nothing fast about 2 bags at a time. The first 2 bags you mixed will be curing by the time you get to the last 2 bags. You want concrete to be placed and finished at about the same time.

It totally depends on the concrete you use and its set time. Real concrete sets in 24 to 48 hours and has 99% strength at 28 days. Calling "fast set" - concrete - is like calling a microwave TV dinner a steak.

 

[JHZR2]

- YT Vids: believe it or not, there are some good YT videos out there that show how to DIY this kind of stuff.

All great info, thanks! I had to chuckle about YT because this “dry pour” is all the rage on the videos lately…. Can’t say my lazy side opposes… but no way would I do it for my needs.

 

[alarmguy]

Some concrete tips:

Always keep the water/cement ratio as low as possible for better strength.

Try and keep the concrete wet while curing you will add more strength to the concrete. This can be done several ways. I have used drip lines, sprinklers, wet burlap bags, covered with plastic. Sealers, but the idea is keep concrete hydrated for proper curing.

Do not pour during extremely high temperatures, you do not want to overheat the concrete.

Add 6-8% air entrainment if concrete will be exposed to freezing

If you need a higher slump, use a plasticizer but never more water.

My home builder at our request tore up the driveway at our new home and put in a new one. Too many imperfections.
Agree, anyone looking to pour new concrete should take 30 minutes and do a search/read on proper curing of concrete. It's a huge misperception that concrete is supposed to dry. NO it's not, its supposed to cure and keeping it moist makes for stronger cement and less to no cracking.

With the new pour they put down plastic first on the dirt before the concrete was poured to prevent bleeding of the soil/mud under the new concrete from pushing up.
A few hours after the pour I kept the concrete wet for 7 days. Driveway was done in two separate pours (long story, ran short of concrete and had to redo the last 1/4 because when they did run out by the time the truck came to finish, it poured rain jsut as they were finishing) but for the first pour since I am now retired, every two hours or so I sprayed down the concrete with water to keep it wet while it cured, first three days are critical but I did it for 7, slowly tapering off around day 6ish. I waited a full 10 or 11 days before driving on it.

For the second pour for the last 1/4 of the driveway. I wasnt going to be as available and the weather, sunny dry and hot, so I bought a sprinkler timer and cheap sprinkler that turned on for 5 minutes every two hours, this really automated everything. Result is a nice driveway with no stress cracks of any kind.

This is when they came back to replace the last 1/4 of the new pour. You can see the plastic that they lay down first. I hear this is standard for home foundation slabs but not walkways and driveways. Its a necessity in this area they found out to include driveways.

 

[2005jettatdi]

I did a pour of 112 square feet in June. It came to 1.5 yards. I considered 60 pound bags from Home Depot (80 pound bags are too heavy for me these days). Redimix was $ 313. I went with redimix. I had to haul the concrete a short distance, but I have a toy Kubota tractor with a loader and that made it a lot easier. I made a bullfloat out of a 3' piece of 1x8 with a 2x3 handle. There are examples online of how to do that. You still need to finish the slab as it hardens. The slab came out fine. Keep in mind, concrete is a chemical reaction that sets, not dries. For a good slab keep it damp for 10 days, 30 days is even better.

After that I needed a perimeter pour around the slab that I used 17 bags of Home Depot concrete for. I found my Harbor Freight mixer could take two bags, about .9 cubic feet. That pour was for drainage and did not need a good finish.