Garage Floor

Question:
I have a large two-car detached garage that was built in 1960. The garage is in great shape, but the floor has several cracks in it and the cement has shifted making the floor uneven. I would like to use half of the garage as a workshop, but none of my tools (i.e. table-saw, router-table) will set level without shimming the legs, which doesn't seem very safe. In addition, the un-even floor prevents my garage doors from sealing competely at the bottom when they close.
I've already cleaned the floor thoroughly and I filled the cracks in with vinyl cement patch. I believe the cracks were due to several trees growing very close to the garage. They have been removed.

I'm looking for advice on leveling the floor for a safer workshop and so my garage door will seal shut.

Answer:
Slab jacking may be able to even out the tilted segements. But also keep in mind- a properly laid garage floor
level- it is ever-so-slightly dished towards centerline and also toward door, so that rains/snow/etc that drips off car has somewhere to go.
Ponding in a garage, especially if it is full of salt, makes slabs die young. That is why machine tools and workbenches (the premade kind) have adjustable feet.

I'd call the slabjacking guy- if they don't think they can fix it, they will turn down the job. In that case, you are faced with demolishing part or all of the slab and repouring- which is not as big a deal as it sounds. you can rent a jackhammer (and earmuffs) and do it yourself, or pay someone to come in with a real jackhammer and knock it out in a day. Clean out and level the substrate, modifying as needed, put down new mesh and/or rebar, and call in the concrete guys. Also a good opprotunity to add full footer under garage door, if builder cheaped out and left a gap there- that is a real common cause of garage floor failures like you described.

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