Do I need a vapor barrier under my slab?

Yes for any enclosed or heated building, and for any slab that will get flooring or store moisture-sensitive equipment. A 10 to 15 mil poly barrier over the base stops ground moisture from wicking up through the concrete.

Rebar grid or fiber for a shop floor?

For shops, garages, and anything that will carry vehicles or equipment we use a #4 rebar grid on chairs, usually at 16 inches on center, plus thickened edges. Fiber alone is fine for lighter, unenclosed pads.

How thick should a shop or garage slab be?

Four inches is standard for a car garage. Five to six inches with thickened edges and a stronger mix is the call for shops with lifts, trailers, tractors, or heavy equipment.

Can you tie a new slab into an existing one?

Yes. We drill and epoxy dowels into the existing slab so the two move together at the joint, then match elevation and finish as closely as the old slab allows.

Concrete Slabs in Chattanooga, TN — Garages, Shops & Barns

A building slab has one job: stay flat and stay put under load, for decades. The difference between a slab that does that and one that cracks and heaves is all in the prep — the base, the moisture control, and the steel. JMF Concrete Co. pours slabs across Greater Chattanooga and North Georgia for garages, shops, agricultural buildings, and light commercial.

What we pour

Attached and detached garage slabs
Shop, workshop, and hobby-building floors
Pole-barn and metal-building slabs
Pavilion, carport, and outdoor-structure pads
Equipment, generator, and tank pads
Agricultural and storage-building floors

How we build a slab

Strip and grade. Topsoil off, cut to grade, and undercut any soft or organic spots.
Base. Compacted crusher-run, typically 4", proof-rolled before anything goes on it.
Vapor barrier. 10–15 mil poly under enclosed or heated buildings and anything getting flooring.
Steel. #4 rebar grid on chairs at 16" on center, or engineered fiber for lighter pads.
Thickened edges. Turn-downs at perimeter walls and door openings where the load concentrates.
Placement. 4" for cars, 5–6" and 3,500–4,000 PSI for shops and equipment.
Finish. Steel-trowel for a hard, smooth interior floor; broom for exterior and traction.
Joints. Sawcut control joints on the right grid so the slab cracks where you can't see it.

Coordination before the pour

Under-slab plumbing and electrical sleeves, anchor bolts, and equipment embeds all get set and checked before concrete. If you're building the structure too, see foundations & footings.

Common questions

Do I need a vapor barrier?: Yes for enclosed, heated, or floored buildings. It stops ground moisture wicking up through the slab.
Rebar or fiber?: Rebar grid plus thickened edges for anything carrying vehicles or equipment. Fiber is fine for lighter unenclosed pads.
How thick for a shop?: 5–6" with a stronger mix if you'll run a lift, trailers, or a tractor. 4" for a standard car garage.
Can you match an existing slab?: Yes — we dowel into it so the two move together, and match elevation and finish as close as the old slab allows.

Concrete slabs for garages, shops, barns & pavilions

What we pour

How we build a slab

Coordination before the pour

Common questions

Slab service area

Chattanooga

East Brainerd

Hixson

Ooltewah

Ringgold, GA

See recent work

Building a shop or garage?