32x50' slab.
Will be 6 bag, 4500psi concrete, 5" slab

No idea which is cheaper, just seeing what others have done.

If I do go rebar, should I go #3, or #4? Was planning on 2' centers.

Rebar in the perimeter AND mesh in the field.

Rebar though out if money is not an issue,wire and fiber otherwise.

mine is 30x50,one key joint down the middle.3000 psi w/fiber,5" thick.no rebar or 10/6 and it's been great for 5 years now.

32x16x6". I had rebar lined up... got asked by the inspector if I was building a bomb-shelter...

Pulled up the re-bar, took it back, and put down mesh. wired it together, overlapped it by a couple feet.

One plastic pre-crack strip at the 16ft mark...

I was told it was unnecessary to have any reinforcement.. and if I were insisting on putting it in, it was better to put in the mesh, and take the money saved and put an extra inch or two of concrete in. (Hence the 6" instead of 4".)

I guess it all comes down to what you are going to have on the floor at any given time.

Are you only going to have little Trucks like 1 ton pick ups etc or a over loaded Tri axle grossing 100,000 pounds sitting inside for periods of time.

12,000 pound tractors will be sitting on it for extended periods, nothing much heavier than that

a lot of it has to do with the prep work and the base. good prep and base will reduce the need for rebar and wire/fiber will help

I had a 30'x40' poured and it is 6" thick with standard 3000psi concrete. It has fiber in it and only rebar for the footers and perimiters as required by building code here in Northern NM. It is a 36" footer by one foot wide, also code here where I live. I have no rebar or mesh in the middle part and have had no trouble at all and it routinely has a 25K Internatioanal winch truck on it. The fiber is all you need in my opinion. My concrete guy said the mesh is a bitch and can cause rust internally throughout the slab which makes air pockets and makes it weaker, but I am not a concrete guy so thats just what he said. My buddy runs the testing and quality control here in town for a major supplier of concrete and gravel so I always ask him. In his opinion and the way roads and bridges are built the 3k concrete is more than enough with no rebar or mesh in the middle. A bridge here is only made with 4500 psi concrete and thats for any kind of weight or abuse so take it for what its worth.

I welded up some scrap angle into 90 deg. pieces and dropped about 3 in each corner of the foundation, then used an old chain link fence in the floor.

How tight do you want the cracks to stay? I used wire mesh and 10m(3/8") rebar on 4 ft centres. I wish I used more as I have 1/32" or so cracks every 16ft. The mesh is keeping them interlocked though.

We did rebar and wire mesh on our driveway slab - guess I should tunnel under it :D

When I was helping my uncle bust up an old shop slab ( from the 30s ) , we found they used an assortment of items. engine heads, iron fencing, tools and even a windmill. :grinpimp:

Last time we did a slab we used 19mm rebar on 6" centers but the rebar was free and the concrete was not...

I am no expert in concrete but I would spend a little more and get some rebar 12-16" on center. 12000lbs is a heavy load on 4 wheels. We have 10"s where we are at right now and our heaviest CNC mill comes in at 20,000lbs with a 6 bolt footprint. Our next building will have 7" concrete (6000PSI) with rebar 12" on center. We have a 50,000lb forklift that moves our big equipment around and it likes to destroy the skirts. When you say 12,000lb your in the same neck of the woods and the lite duty concrete may not like the load. Not sure I am not an expert but have some limited experience.

depends a lot on what kind of soil you are putting it over

concrete cracks. end of story

Last time we did a slab we used 19mm rebar on 6" centers but the rebar was free and the concrete was not... Holy shit, #6's at 6 inch OC.:eek::eek: Why all the extra work? I would have put them at 12 and took the rest in for scrap. #4's at 12 is suffucient for damn near anything that we would ever use.

I ended up going with 1/2" rebar on 24" centers. Was almost the same price as mesh.
Rebar was $5 for a 20' piece, Mesh was $26 for 8x15.
My base is a pretty compact gravel floor, Im not worried about it at all.
Concrete pour will happen Friday, build thread to follow.

Me.. I would put #4 bar on a 24 in pattern. I would add a bar onthe edges for a 12 inch pattern. Bar is cheap

me.. I would put #4 bar on a 24 in pattern. I would add a bar onthe edges for a 12 inch pattern. Bar is cheap

x2

Did anyone use plastic under their pour? My friend didn't and his slab sweats in the winter, totally soaking it. He recommended that I seal it with plastic before I pour.

For sure do the plastic....Its cheap and being able to work on something in the dry is the whole reason for the shop...right?

Level it out and water it eveyday heavy for a week. That will settle the dirt down good and tight. Pour it at 5" and if you have the money rebar is the way to go!!! Wire will work and if you pack it hard enough and pour it 6" you shouldnt need anything.

But I always building things to the extreme so i would use rebar, plus its more simple to pour on then wire:D

Did anyone use plastic under their pour? My friend didn't and his slab sweats in the winter, totally soaking it. He recommended that I seal it with plastic before I pour.

How far above ground level are you?? If water will drain away you should be fine

I don't think my shop floor has wire *or* rebar in it...

Holy shit, #6's at 6 inch OC.:eek::eek: Why all the extra work? I would have put them at 12 and took the rest in for scrap. #4's at 12 is suffucient for damn near anything that we would ever use.

The free rebar also came with a couple of rodbusters and a boom truck to lay the rebar, our only direct cost was buying the busters lunch, supper and beer...