How do i build a concrete slab?

Question

I want to build a 12x12 concrete slab its only gonna be used to anchor some industrial metal shelving w/ sheets of metal or plastic for sides and roof, it will primarily be storage but will also be used to work on small motors and so will be exposed to gasoline, oil, etc. I live in CT and we get some real good freezes here how thick does the slab have to be? Do i need to use rebar? and can i just dig the hole and pour or do i need to do the whole stone and sand thing first?

Answer 1

u dont need rebar, just dig out the area..make sure its level..build forms around area...and pour concrete about 4 inches thick...u might want to rent a mixer if your doing it yourself...thats gonna take quite a few bags of cement

Answer 2

You need to determine what the frost line is in your state and dig footers on the edge of your slab down 6" to 1 foot below the frost line. The footers should be at least 6" wide at the bottom and should slope up to the bottom of the slab on a 45 degree angle. Your slab should be at least 4 inches thick, 6 inches is better. It would also be better if you had rebar in your footer and at least some welded wire in your slab.You will need to dig out the slab to get the elevation of the slab above the ground to where you want it. Make sure there is clean soil below the slab, no organics. You may need to over excavate and backfill to get a good base. Make sure you compact the area with a plate compactor and the soil should be damp but not wet. If you have to oversxcavate and backfill, bring the level up in 6 inch lifts and compact between lifts. Dig the footers last so you don't disturb the main slab area. Put down a plastic sheet as a vapor barrior on top of the soil. Do not let any of your rebar touch the dirt, should be 1 to 2 inches from the edge of the concrete (bottom surface). Vibrate the footers when you place the concrete to assure you don't have any voids, but don't leave the vibrator in one place too long or you'll seperate the aggregate from the concrete mix.

Answer 3

The best place to go is to your local building department. There are two reasons. Firstly, they will let you know what the local codes are, and second, you may need a permit for that size shed.

In your area, you will probably need to have footers for a slab that size, somewhere between 12 and 30 inches deep, probably about 18 inches. The rebar probably won't be necessary, though it is a good idea.

My guess is that you can just pour the concrete. Again, the building department may have their own ideas.

Consider sealing the slab, possibly with an epoxy to prevent the oil and gasoline from seeping in. The last think you want is a couple of tons of concrete that have to be removed because they are declared a hazardous waste in the future.

Answer 4

Yes you can do that. Generally a 2 stage process as different concrete is used on the floor than on the foundation. What you got to do is dig a ditch alongside the outer wall(more or less getting under the walls - or at least partially under) and down a couple of feet. Code is 4ft, so basically what you are doing is building the foundation wall (after the fact). You probably can dig out all four sides that way. And anywhere else there is a support wall. That is the "grunt work". Once that is dug out lay in re-bar and tie it together. Then the concrete can be poured in there to build the walls. Not quite up to top of floor height, just to fill in the ditch you dug.. After that hardens you can prep the floor surface. If it is just a large steel barn, then lay re bar on the floor in a criss cross pattern and tie together and support up the air with stones.. This is so the cement will get under the rebar and be in the cement. Now get a big cement truck in there to pour the entire floor. Smooth. Job done.

Answer 5

You need to form the outside with either wood or metal. For a slab to be good you need to have a 12" footing around the adges. For it to last heavy use you need it to be between 4"-6" inches. Use should definatley use rebar and cement mesh which comes in rolls of about 750 sq. feet. Make sure your base is stable, here we don't use sand and stone but you do want to make sure the ground underneath has seattled especially if you add in dirt. Make sure to include your footing in you cement yard calculations as this can make a BIG difference. There is a website online called the concrete network which maybe very helpful.

Answer 6

You first have to determine the weight to be supported. The weight bearing characteristics depend on the thickness. You have to have a smooth, solid, level surface to pour on, or your slab will crack and deteriorate, a fine dirt base is preferable. Also the depth at which you set your rebar will affect your strength and also is determined by temperature. If you poured a 4" to 6" slab and set your rebar in the middle you would probably be OK. Go to your local library and check out a book on concrete work. Home depot employs general contractors so ask them too.

Answer 7

Dig footings around the slab area at 2 feet deep cross tie rebar in the footings and then tie the footing rebar to rebar in the slab area the slab rebar shoueld be about a foot apart and crossed making 1 foot squares. then order your concrete with fiberglass in it and do what is called a monolythic pour. this is where you pour the footings and the slab at the same time. without the footings the slab might heave with the deep frost. Good luck. Slab should be 4" thick

Answer 8

Build a concrete box in the shape you want the slab to be in. Then tie rebar together with strong wire. Pour and set.
(Don't take my word for it, call a conractor and don't hurt yourself.)

Answer 9

You will need to check your local building code.
It will tell you how deep the frost line is and how thick to pour

Answer 10

go to ask.com