Garage & Shed Slabs in Sioux City, IA

Garage and shed slabs are the floors your vehicles, tools and storage sit on, and they have to stay flat for doors to close and walls to stay square. In a city where the median house dates to 1957, plenty of garage floors are as old as the house and have cracked, heaved or sunk toward a floor drain or the door. We replace old garage floors, pour new slabs for garages and sheds, and build pads for workshops and outbuildings.

Replacing an old garage floor

An old garage floor usually fails at the door, where water and salt from the cars collect and the slab meets the driveway. Other signs are cracks that shift, a floor that slopes the wrong way, and broken sections around posts or drains. Replacing a floor inside an existing garage means breaking out the old slab without damaging the walls, rebuilding the base and pouring a new floor with a slope toward the door so meltwater from your car drains out.

New garage and shed slabs

For a new structure, the slab has to fit the building plans: exact size, square corners, level where walls sit and anchor bolts in the right place. HomeGuide lists two-car garage floors as typically 20 by 20 to 24 by 24 feet and 4 to 6 inches thick, and shed slabs as typically about 4 inches. Whether a garage or larger outbuilding needs footings below frost depth or can sit on a slab depends on the building and on local code. We check with the city or county building department on that before we form.

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The base and the soil

Loess soil is firm when dry and soft when wet. A slab that sits on soft or uncompacted ground will settle, and in a garage that means cracked floors and doors that no longer seal. We strip topsoil and organic material, compact the subgrade, and place a compacted gravel base. A vapor barrier goes under slabs where moisture from below matters, such as a heated shop or a garage that will get a floor coating later.

Reinforcement and joints

Rebar or wire mesh is placed on chairs so it sits in the slab, not on the ground. Control joints divide the floor into panels so shrinkage cracks follow straight lines. We thicken the slab at edges and under heavy loads such as a lift, a workbench with heavy equipment or a trailer parking area.

Planning for later

If you want a floor drain, heat in the floor, an epoxy coating or a lift, tell us before the pour. Those are easy to plan for now and costly to add later. Give a new garage floor about a week before parking a car and keep salt-laden slush off it the first winter where you can.