Side by side
| Factor | Repair and coat | Replace the slab |
|---|---|---|
| Cost, typical 2-car garage | $4,000-$7,000 | $8,000-$15,000 |
| Time | 2-3 days | 2-4 weeks including cure |
| Fixes surface spalling | Yes | Yes |
| Fixes cracks | Chased and structurally filled | Eliminated |
| Fixes settlement or heave | No | Yes |
| Fixes drainage and falls | Partially, by resurfacing | Fully, by re-pouring to grade |
| Disruption | Low | High, saw cutting and removal |
| New concrete must cure before coating | Not applicable | 28 days minimum |
| Result once finished | Sealed, level, protected | New slab, still needs coating |
Gold marks the stronger option for that factor. A tie is shown in neutral text.
Repair and coat when
The slab is sound and ugly. Surface spalling, salt scaling at the door, dusting, old coating failure, static cracks and pitting are all surface conditions, and all of them are ground back, rebuilt in resin mortar and coated in a two to three day visit. This describes the very large majority of the old garage floors we are called to look at, including plenty the homeowner had already written off.
Replace when
The slab is moving or broken through. Cracks wider than about six millimetres with a vertical step across them, a slab that has settled against the foundation, exposed and rusting reinforcement, or a floor that drains toward the house are structural problems, and a coating over any of them is money spent on hiding something that will come back through. In those cases we say so and we do not quote a coating.
A new slab still needs everything
Replacing the concrete does not get you a finished floor. A new slab has to cure for at least twenty-eight days before it can take a coating, and it arrives with a hard trowelled surface that has to be ground open exactly like an old one. Anyone budgeting a replacement should carry the coating cost on top of it, and should plan for the floor to be unusable for over a month.
Not sure which applies to your slab?
The site visit includes a moisture reading and an honest look at the concrete, then a written fixed price. We will tell you when the cheaper option is the right one.