Looking for info on how to pour a slab

[Gary Fowler]

I watched a tract home builder building the home next to me when I lived in Houston, Texas area. He came in with a dozer and stripped off the grass from the wet black clay, hauled in several dump truck loads of sand for which he had to use the dozer to pull the dump trucks in and out, then dug in the underground sewer lines. Backfilled with Bobcat by just pushing in the sand; I never saw any compactor on the premises. He then threw up some 6x planking for forms and here comes the concrete trucks. If that slab isnt already cracked it for sure will be soon. Only steel in the slab was 6x6 wire mesh that was laid on the plastic vapor barrier and may or maynot have even been pulled up in an attempt to get it mid way of the slab. This is the way most tract homes are built which is why most of them have cracked slabs in the Houston area. They should really be built on concrete piers with a floating slab on top due to all the highly expansive clay soil but there is no code there that requires it.
You have to have a well compacted substrate for the concrete to set on, otherwise it is going to crack. Minute drying shrinkage cracks are to be expected in any slab, but these wont hurt your foundation. It is the settling of the soil underneath that has destroyed many houses.
Put lots of effort into getting good compaction of the soil base especially over your sewer trenches where native soil has been displaced. Here in Bismarck, we have rocks with some clay to hold them together so it is a good foundation to put concrete on. Some other places are not so lucky.
PS: I spent $12,000 putting in drilled piers to fix the cracked slab on my former residence due to the same type of workmanship described above. There is no way in he!! I would ever buy another tract built home. They are all just thrown together regardless of the final price. They put a $2000 foundation under a $400K home and call it good.

 

[scott_vt]

Good Evenon dablack,
About 1 1/2 yrs ago we built a 28' x 42' barn. We had 3 guys inside the formed area moving concrete and power screting...

One guy on the outside, that was me, instaling J bolts around the perimeter. We had 3 concrete trucks each carrying about 8 yds each, showing up at my property way too quickly, they were supposed to be spaced out ..... time wise !

This is a huge amount of work, believe me !

After all the dozer prep work was done we compacted the form area and then compacted some more, cant do enough of that !!! We also put dow plastic vapor barrier, and used wire reinforcing mesh over the whole slabbed area !

If your planning on doing it yourself make sure you have plenty of EXPERIENCED help around !

After the slab was completely poured , we got out there and power trowled it until it was smoth as a babies ***** ... lots of work but worth it JMO, as others have said once its done its done !

Good Luck !

BTW the slab was 6" thick and about 10 to 12" just around the perimeter .

 

[bironacad]

Do a Google on "Slab on Grade", " preparation for concrete slab" , "pouring/finishing concrete slabs", etc.

When you are ready to pour have one or two fellows familiar with concrete on your crew. One on the chute and the other finishing. It'll make your day go a lot easier. Try and pick a cool day if that is possible.

It surely will be nice having Rent Money go to Materials!:thumbsup::thumbsup:

Sound like experience talking.

 

[Egon]

It's very old and out of date experience. Thank God.:laughing:

Only thing worse is Asphalt.

And then comes base preparation to very close tolerances so very little expensive product is not paid for.:thumbsup:

 

[bucktaker]

Speaking from experience if you have never done concrete work before hire this out. Too big to handle without experience. You may be able to find finishers through your concrete supplier thats what I did they fixed my unlevel pad 40x64 and machine finished the floor.

 

[Pete Judd]

15-20 years ago, I did a 50 yard pour, the pump truck showed up late (after 5 pm) had 3 concrete trucks siting on the road doing nothing but waiting, 80 + day. No overtime charges to me, but they were all in a hurry. I was in a lot better shape then, but it was still a short handed pour, could of had a couple more hands. As fast as the first truck was unloaded, it was off to get another load, same with the second. third truck had to come back half loaded. Yes I did all the prep work myself, built the forms, laid all the rebar set on pylons, planned for all the stuff coming up through the slab, rented the power trowel, and some other tools to get it done. I think that I saved some money, but not sure looking back, as it may have taken other tolls on the body, But it was one learning expercince. I think I would hire it out now.

 

[Cat_Driver]

The best advise I can five you is to always add fibers to the cement. Either stainless steel or other material.

I poured a 4" slab on the equivalent of beach sand with no base and it takes fork lifts, track skid steer and other trucks with no problem.

I don't get freezing and other things and the slab isn't huge. I did it more as an experiment and it is holding up better than the back dock slab a "professional" contractor installed. His is full of cracks and mine poured with fibers doesn't have a crack yet.

 

[Deere Dude]

Ok guys. I'm new here. We just bought property in the Rusk TX area and we are planning on building debt free. The first thing I would like to build is a 24x45 garage. I will frame it for garage doors but initially, it will be for living in so we can get out of rent. I'm thinking a story and 1/2 with bedrooms and a bathroom upstairs and then the downstairs will be 100% open. Put cabinets along the long way (oposite of the garage doors) and living / dining will be out in the open. Used fixutures, used windows, used doors.....so and so forth. I would like to get out of rent ASAP.

Anyway, I don't have any problem with the building of the structure, but I have never done any kind of concrete work. I have googled until my eyes hurt but can't really find anything.

Is there a book or website out there for a DIY guy like myself where I can see how to form and prep for the pour. Can I just put forms on solid ground or do I need to dig and put gravel? I just need more info.

thanks
Austin

What is the minimum sized pour without a surcharge in your area. If it's not to much and it sounds like you are handy, maybe you and 1 other person could do it in stages.
I'm not a mason by a long shot, but me and my wife can do maybe 6-7 yards of flatwork and I am shot after that. Maybe you could do your project in small chunks.
If you get help with one stage, at least you will get the feel of it and be able to do the rest, and then you will be handy enough to tackle the approach and whatever else comes up.

 

[Gary Fowler]

Personally, I would do it in one pour. Joints in a building slab are not desirable. Do what work you can and have the experience for and hire out the pour and finish work. You will be glad you did.
It takes at least 3 experienced folks to make a pour. You need 2 people on the screed and one with a comealong pushing or pulling the concrete to keep it level with the screed. That is assuming that the concrete truck has capabilty of moving the chute from the driver seat. If not, add one more person working the chute. If a large area of more than 10 yards, you need 6 or 7 so you can swap out and give the guys a rest(chute man shouldnt need a replacement) Even if the concrete truck driver is good and places the concrete evenly, there is still a lot of comealong work to pull the concrete into place, tamp it and rough screed it off. In cold weather, you have much more time to do this, but above 75 F you better have it down in 2 hours or so or you will be in trouble.

 

[dablack]

Wow guys. Lots of great info. I will for sure I will have a crew there for the pour. I was mostly trying to figure out exactly how much of the prep work I could do myself and how much prep work there was. I just haven't never really looked into foundation work because all the work I have ever done has been rebuilding what was already there, never building from scratch.

About the engineering of the slab.....well, I'm an engineer.....

I'm not the correct type of engineer but I am working from plans and the slab is spec'd out. So, I should be good on correct thickness and how thick it needs to be around the perimeter.

Looks like my main problem is that I have no mean to compact the base mateial.

As for the services, under the slab, I'm only going to have a drain. Power and water can come in above the slab.

I will have to look into it more and get some prices from local contractors.

Thanks again to TBN.

Austin