Garage & Shed Slabs in Bloomington, IN

Garage & Shed Slabs are the floors under detached garages, backyard sheds, pole barns, workshops and carports. Unlike a patio, a building slab has to be level, square and the exact size the building needs, because the walls go right on top of it. If the slab is off by an inch at one corner, the framer fights it on every wall. Out in Monroe County and the hill country around Bloomington, pole barns and shops are common, and so are sloped, wooded lots where getting a level pad takes real site work.

Planning the slab

We start with the building plan. The slab size, the location of doors, any thickened edges for walls, anchor bolt or post locations, and where water should drain all come from it. A garage floor usually slopes slightly toward the overhead door so melting snow runs out. A shop that will hold heavy equipment or a car lift may need a thicker slab or thickened areas under the posts. If the building needs a permit, the slab usually does too, and we check that before we dig.

What goes under it

Soft soil and organic topsoil come out. On a slope we cut and fill, compacting fill in layers so it does not settle later. Bloomington sits on karst limestone, where soil can slowly wash into openings in the rock, so we take soft or unusual spots seriously instead of pouring over them. A compacted stone base goes down. For enclosed buildings that will be heated, finished or used for storage, a vapor barrier under the slab slows ground moisture from coming up through the floor.

Depth and steel

HomeGuide's slab guide prices 4-inch slabs at roughly $6 to $8 per square foot and 6-inch slabs at roughly $8 to $10. Four inches is enough for a typical shed, or a garage that holds cars on firm soil. Six inches, or four inches with thickened edges and pads, is the better fit for pickups, tractors, campers and heavy shop tools. Rebar or mesh sits on chairs at mid-depth so it actually carries load instead of lying in the dirt.

The pour and finish

Garage and shop floors usually get a steel-trowel finish that sweeps easily and can take an epoxy coating later. Shed and barn floors can be troweled or broomed. Joints are cut to divide the floor into roughly square panels, and anchor bolts or straps are set into the wet concrete when the framer needs them. The floor then cures before any walls go up.

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When you need a new slab

• Building a new detached garage, shed, pole barn or workshop
• Replacing a gravel or dirt floor in an existing barn or shed
• An old garage floor that is cracked, sunken or holding water
• Adding a carport or lean-to that needs a hard surface
• Pads for generators, HVAC units or equipment

Caring for a building slab

Keep water from running into the building by maintaining gutters and grading. Clean up oil and chemicals before they soak in. A penetrating sealer or a floor coating protects a garage slab from salt brought in on tires during winter. Fill cracks early so water does not reach the base.