cement slab

[lovemytoys]

this will be my first slab .any input would help alot.slab is going to be 14'x20'x4".i dont think i can do it with a small mixer so i think im going to order a truck.do i need gravel and a vaper barrier?? also i heard the the outside edges 8"back should be 6" dep. i hope i said it right .they say it will help with shifting and frost lift .what do you think

 

[dodge man]

4" in pretty thin, thats what is used for sidewalks, but not much else. I would also look at some kind of mesh or rebars. Thats also big enough you would want to cut in a few joints to control cracking.

 

[Mousefield]

The 14 X 20 ft, is that for a garage? Depending what is going on or into this space the 4 inch may not be enough. The base is very important as you do not want any settling after you have poured the slab. If it has settled then driving a car on it for example could easily crack the slab. Both the thickness and amount of cement in the mixture needs to be considered. The more cement (within reason) in the mixture the stronger it will be, still has to be mixed in perportion to the sand/rocks. In our barn floor, which was poured after we built the barn, the cement company used an MPA 25 instead of MPA 20. This made for a stronger floor in our barn. As others have suggested some steel mesh or rebar could be considered.

 

[flusher]

this will be my first slab .any input would help alot.slab is going to be 14'x20'x4".i dont think i can do it with a small mixer so i think im going to order a truck.do i need gravel and a vaper barrier?? also i heard the the outside edges 8"back should be 6" dep. i hope i said it right .they say it will help with shifting and frost lift .what do you think

Here's what the site prep looked like when the 24x42 ft slab, 6" thick, 4000 psi concrete, 4" slump was poured for my shop.

This is the trench for the 100 amp 220V service to the shop connecting with the slab footing.



Some images of the site prep work. The footings are nominal 12"W x 12" deep. The black plastic is 6mil Visqueen. The rebar is #4 (1/2") on 24" centers both ways. The rebar under the slab is supported by 3" tall doobies to keep it centered top to bottom in the slab.







You'll need a minimum of 3 guys to do the pour (one on the chute and two with shovels). Then you need the equipment to float the surface and put whatever finish you want (trowel, broom, etc). If you've never done this, then get some experienced help because it's easy to screw up the finish on the slab if you're not careful.

Good luck.
P.S. Concrete work is one of my least favorite jobs, after plumbing.

 

[timswi]

I'd go at least 5" with fibergass..Makes a strong slab as well.

 

[lovemytoys]

this a big shed.i will be using it for storeage of my bx24 -lawntractor and screen house .

 

[Egon]

they say it will help with shifting and frost lift .what do you think

I think they may not have know much about frost lift.

 

[Duffster]

You'll need a minimum of 3 guys to do the pour.

Or 1 good guy or 2 mediocre guys.

 

[lovemytoys]

so i will up it to 6"x14'x20' add wire role out .could it be one slab or do i need to break it up .im hopeing one slab. vapor barrier then 4"gravel them 6"cement

 

[Duffster]

so i will up it to 6"x14'x20' add wire role out .could it be one slab or do i need to break it up .im hopeing one slab. vapor barrier then 4"gravel them 6"CONCRETE

I would NOT break it up into more than one pour. Don't waste your time with rolled wire mesh. Use 3/8 rebar.