Cars and storage: the standard call
A garage that holds vehicles, bikes, mowers and everyday storage runs on the same 4,000 PSI air-entrained standard we build to across driveways and other exterior flatwork here. A standard garage floor, poured as a slab on grade, handles typical rolling loads and stands up to the freeze-thaw cycle an unheated garage floor sees along with the rest of the slab.
Point loads change the math
A car parked on a slab spreads its weight across four tire contact patches, each one small but distributed around the floor. A vehicle lift, a jack stand, or a piece of stationary equipment concentrates its weight onto a few fixed points instead, sometimes just the size of a post or a foot. That is a harder load for a slab to carry than the same total weight rolling around on tires, and it is why a shop floor gets looked at differently than a floor that only ever holds parked cars.
- A parked car: weight spread across four tires
- A vehicle lift or equipment: weight concentrated on a few fixed points
Thickness rides along with strength
Garage slabs already run thicker than driveways as a matter of course, five inches against four, priced at $8 to $12 per square foot installed. Point loads from a lift or heavy equipment can call for more than that standard five inches, along with the stronger mix, and that gets sized to the specific load at the estimate rather than guessed at in general.
Reinforcement, wire mesh or a tied rebar grid, is a related but separate decision, and one we would rather walk you through in person than default to one or the other here.
What we need to know before the pour
Tell us plainly what the garage is for. Cars and storage is one answer. A shop floor with a lift, welding, or equipment that will sit in one place for years is a different one, and it changes the mix, the thickness, and possibly the reinforcement, all decided together at the estimate rather than added on after the fact.
A slab poured for the wrong use is expensive to fix
A standard garage floor poured under a lift that goes in later is not a quick problem to correct. Adding strength or thickness after the fact usually means breaking out the existing slab and pouring again, not topping it or reinforcing it from above. That is the whole reason this question is worth answering honestly before the pour instead of guessing and hoping the garage stays a garage.
If there is any real chance a lift, a kiln, a compressor, or something else heavy and fixed goes in down the road, say so at the estimate even if it is not certain. We would rather spec for a maybe now than tear out a floor later.