5" to 6" of six bag mix with 6" mesh will hold most anything you want to put on it, Instead of using the Polystyrene under the concrete for insulation i would go with the new bubble foil. The problem with the polystyrene insulation is that is a heavy load is placed on the floor it will compress and ripple the floor causeing it to crack. now it has to be VERY heavy like a loaded semi. I would for sure do infloor radiant hot water heat. i just got done helping my neighbor do his 60 x 90 shop and it's a nice and toasty 70 in there right now. and if you are going to be working in there in the summer have a HVAC guy install you an air handler with an A coil and a condensor outside for the A/C and you will love it year round. and make sure you place that air compressor in an INSULATED room nothing will drive you insane faster than listening to that thing run. and most important have fun and enjoy it

 

Make sure and put LOTS of ventilation in your compressor room!

 

Whatever the temp is, you've got to divide it by at least 3 to get the feel for a cold cement floor. Cold to the bone at 50.

 

Unless you are going to take the time to prop up your wire mesh so it will be centered in the slab it is useless. Just pulling it up will end up with most of it still on the bottom. While harder to finish if you add fiber mesh to it you will likely be in better shape than the normal wire mesh.

Four inch thickness with a 1 foot by 1 foot thick strip anywhere that will be bearing the weight of the building is the min. I would also recommend the two by two footings reinforced with re-bar that are mentioned above for the lift. If you can swing it the outer foundation mentioned above is also the ideal setting, just make sure you know the exact with and placement of any and all door openings, otherwise it is a pain in the rear to change them later.

I would also recommend a 6 bag mix.

I am only 23 but have been been running concrete jobs for my dad when we had more than one pour in a day since age 12 (it is just side income for us) and started doing them for my self at age 16. Been messing around in it since probably age 8. By no means am I the be all end all of concrete knowledge but I know a bit about it and from practical experience can make these statements.

 

I'm with Hillbillywagon. 4" slab, thickened to 12"x12" anywhere that's bearing. The 24" square footings under the slab where the lift bears also sounds like a good idea. Locally, the standard would be 6"x24" foundation walls on 14"x8" concrete footings as a minimum. Standards vary regionally. I draw house plans for a living and occasionally have to redraw plans that were ordered through the internet or magazines. They come from other parts of the country and don't meet local code or local construction standards.

 

I am building a small garage myself 32'x40' x13'high I wantto put the heating in the floor but I realize that it will make it a pain to pour the floor I have the walls up and the roof on. I want to make my own used oil burning furnace is it possible to drip feed oil into a stove add a hot water resevoir on top with a circulator pump has anybody ever done anything similar
ps I am in WV

 

It's not harder to pour the floor with radiant heat tubes in it. The tubes are tied to the concrete wire.

 

I disagree with the idea of only using mesh. If the OP is planning a lift, he's planning some pretty heavy loads in spots. I'd go with #2 rebar...it's a lot stronger and shouldn't be that much more expensive (though I haven't priced rebar lately).

And...I'm totally jealous. I'd love a workshop that size, but I just did a quick calculation, and in my town, the land underneath it would go for about $120K...sheesh.

 

a friend does concrete he says there is two types of concrete cracked and the one that is going to crack . wire mesh will not keep concrete from cracking it just holds it together , curff cuts will allow the cracks to go to them . I poured a 5in floor with wire and for the 5 yrs i owned the garage it did not crack (30x36) had 6in. poured in a fire station and it cracked within a mo. put in to engineers specs.

 

Concrete placed on a weak base and/or with insufficient reinforcement may develop tensile cracking, if loaded heavily enough. Rebar will help to address this. Mesh will not particularly help.

ALL concrete has a strong tendency towards plastic shrinkage cracking. This is a natural result of the hydration process as the concrete cures. No matter how good your subbase is, no matter how much rebar you have in there, no matter how good the concrete, the concrete will tend to crack as it cures.

This latter problem is addressed in two ways:

1) Rebar (or mesh) is used to keep the cracks from growing larger, and to keep the cracked sections from moving perpendicular to the plane of the floor.

2) Crack control joints (not the same as expansion joints) are sawed or tooled into the concrete, typically on a 10 or 12 foot grid. This causes the sections to crack in a controlled way, and this grid spacing is sufficient to prevent unsightly cracks from appearing elsewhere. Look in any big box store to see how this is done. You can also note that it doesn't always work.

 

He must be from NE MN...lol

 

your floor will only be as good as the base that's under it. make sure it's compacted well. only bring in 4" to 6" of fill at a time and pack it WELL!!!