Concrete Garage Floors & Slabs in Flint, MI

Concrete garage floors and slabs are a big part of our work in Flint because so many homes here have a detached garage at the back of the lot. Many of those floors are as old as the house, poured thin on soil, and they have cracked, sunk at the door or broken up where water got underneath. We replace garage floors, pour new slabs for garages and sheds, and set pads for air conditioners, generators and other equipment.

Replacing an old garage floor

When the floor inside an existing garage fails, the walls usually sit on their own footings or a curb, so the slab can be broken out and replaced inside them. We remove the old concrete, dig out soft soil, compact stone, and pour a new floor that slopes slightly toward the door so meltwater from your car runs out instead of pooling. Where the floor meets the driveway apron, we set the height so water does not run back into the garage.

If the walls themselves are leaning or the sill plates have rotted from years of water at floor level, that is a carpentry problem to solve before the new floor goes in. We will point it out at the site visit.

New garage and shed slabs

A new garage needs more than a slab. Michigan's building code rule on frost protection (R 408.30449) sets footings at no less than 42 inches below finish grade unless another approved method is used, and cities and townships around Flint each set their own permit and inspection steps. We confirm the requirements for your address and build the foundation and floor to match.

Shed slabs are simpler. HomeGuide's slab guide says shed slabs are usually about 4 inches thick. We pour them on compacted stone, slightly above grade so water drains away from the walls, with anchors cast in if the shed calls for them.

Thickness and reinforcement

HomeGuide puts a two-car garage floor at 4 to 6 inches thick. We go to the upper end for pickups, work trucks or a car lift, and add rebar or wire mesh to hold cracked sections together. Control joints divide the floor into panels so shrinkage cracks follow planned lines.

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Equipment pads

Air conditioner condensers, standby generators and hot tubs all need a flat, stable base that will not settle and tip. We size the pad to the unit and the manufacturer's clearances and pour it on compacted stone.

Curing and use

HomeGuide's slab guide says a slab is walkable in 1 to 2 days, ready for driving in 1 to 2 weeks and fully cured in 28 to 48 days. Hold off on parking heavy vehicles or setting a lift until the slab has had time to gain strength. Sealing the floor helps it resist road salt dripping off cars all winter.