Can a garage floor be replaced with the garage still standing?

Can a garage floor be replaced with the garage still standing?

Yes, in most Henderson garages. The old floor gets cut free, broken out and carried through the door, and a new slab is poured in its place while the walls and roof stay where they are. Which way the job goes is decided by what the walls stand on, their own footing or the edge of the floor itself. Everything else about garage slabs and floors in Henderson County follows from that answer.

An attached garage on an East End ranch, or in one of the newer subdivisions out toward the bypass, usually has its walls on the same foundation as the house, with the floor poured inside them as its own slab. That is the easier case. The detached garages on the older lots near downtown are the ones to look at closely. Many of them were built the way a new detached garage still is, with the walls set on a floor whose outer edge was poured thicker to carry them.

What are the garage walls sitting on, and how can you tell?

Stand inside and look at the bottom of the wall. If the wood sill sits on a curb of block or concrete a few inches tall, the walls have a base of their own and the floor is a slab poured inside it. If the sill sits right on the floor, the walls are most likely riding on a thickened edge of that same floor.

What else gives it away:

• A crack running parallel to the wall, a foot or so in from it, all the way along. That line often marks where the thick edge ends and the thinner middle of the floor begins.
• The floor meeting the curb with a clean joint, and the curb sitting level while the floor has dropped away from it. The two were never one piece.
• On an attached garage, poured foundation walls showing along the sides with the floor set down between them.

When the walls ride on the edge of the floor, that edge stays. The saw cut runs along the inside of it, the middle of the floor comes out, and the new slab gets poured against the old edge. If the edge itself is broken or has moved, the job is no longer a floor job.

The crew reads all of this on the site visit, at the wall base, along the edge and at the door jambs. When what they find is a foundation question rather than a floor question, they will say so plainly, before anyone quotes concrete.

When does the whole floor need to go, not one section?

When the damage belongs to the whole floor rather than one spot. A floor broken into a grid of pieces, one that has pulled down away from the walls along more than one side, one heaved up at the door, or one that holds a puddle in the same low place after every wet car is a whole-floor job. Patching one piece of it leaves the rest still moving.

The puddle is the one people live with longest. A low spot that holds meltwater off the car all winter keeps the base underneath it wet, and a wet base on clay keeps settling.

A single corner that dropped while the rest sits flat is a smaller job, usually one section cut out and replaced, and that read is in why a slab sinks and what lifting fixes.

How does an old floor come out of a garage and a new one go in through the door?

The garage gets emptied to the walls, then the floor is saw-cut along every wall so it breaks free without pulling at the curb or the edge the walls stand on. A breaker takes it apart, and a small loader carries the pieces out through the overhead door to a truck waiting in the driveway. Tear-out runs $2 - $4 per sq ft as its own line on the quote.

Emptied means everything on the floor. The chest freezer, the shelving units, the workbench, the bikes hanging low enough to catch a loader bucket. The new slab gets finished wall to wall, so nothing can sit in a corner waiting it out.

The new concrete comes in through the same opening. The mixer backs up the driveway to the door, and the chute reaches the front of the garage. When it will not reach the back wall, the crew wheels it in with a power buggy or sets up a pump, and that gets decided on the site visit.

The new floor is quoted against the slab rate, $7 - $11 per sq ft installed, with the base and the steel itemized on the written quote. The prices page has what a garage slab costs in Henderson County alongside the other slab ranges.

How high does the new floor sit at the door and at the step into the house?

A replacement floor has to meet three heights that are already fixed. One is the bottom seal of the overhead door, another is the edge of the driveway outside, and the last is the step up into the house. The old floor has often settled away from all of them, so the crew sets the new grade to those points before any concrete arrives.

The door seal is the one you notice every day. Set the floor low and there is a gap under the closed door that lets in water and blown leaves. Set it high and the door hits the concrete before it finishes closing. At the driveway, the new floor lands flush with the old drive at the expansion joint between them. The step into the house is not moving, so the floor is built to it.

Inside those three points the floor gets a slight fall toward the door. Snowmelt off the car and the water from a hose-out then run outside instead of collecting along the back wall.

What goes under the new floor this time?

A compacted gravel base, placed and packed on the clay before anything else goes in. An older garage floor on the East End or out Zion Road may have gone down on whatever dirt was there when the house went up, and clay that swells and shrinks under a slab with no base is a common reason a floor cracks into pieces.

On the river side of town, where the water table comes up in a wet spring, a vapor barrier goes down over the base as well. The slabs page explains when a slab needs a vapor barrier.

With the old floor out, this is the one chance in the life of the garage to bury anything that should run under it. The thinking on that is in drains, conduit and sleeves under a shop floor. Decide before the base goes down.

When can the car go back in, and does the season matter inside a garage?

The walls and roof help more than people expect. A floor poured inside a garage is out of the sun and the wind, so the surface does not dry out ahead of the rest of the slab on a hot afternoon. The cold is another matter. A shut garage is still an unheated room in November, and a hard night gets into a fresh floor inside as surely as it does outside.

The wait before a car goes back on it is the same as for a driveway, laid out in how long before you can drive on new concrete, and the months that work are on when concrete can be poured in Henderson. Plan on the car living in the driveway for that stretch, and on the freezer and the shelving coming back in last.