How much does it cost to repair and resurface a badly damaged Ottawa garage floor before coating it?

If your Ottawa garage floor has extensive damage from years of freeze-thaw cycles and road salt exposure, repair and resurfacing costs can be a significant part of your total coating project. Understanding what goes into these repairs helps you budget accurately and avoid surprises when contractors quote your job.

Minor surface damage, which includes light spalling, small pits, and hairline cracks, is the most common condition Ottawa coating contractors encounter. This level of repair is typically included in the standard preparation process or adds $200 to $500 to your project. The contractor fills small cracks with polyurea or epoxy filler, patches minor pits with an epoxy mortar, and diamond grinds the entire surface smooth. For a standard two-car garage with typical wear, this baseline preparation and minor repair runs $800 to $1,200 as part of the overall coating project.

Moderate damage is where costs start to climb. If your floor has numerous cracks wider than a quarter inch, areas of spalling larger than a dinner plate, or sections where the surface has eroded down by a quarter inch or more, the repair work becomes more involved. Larger cracks need to be routed out with a grinder, cleaned, and filled with flexible repair material. Spalled areas need to be built back up with cementitious patching compound or epoxy mortar, and these patches need to cure before coating can begin. Moderate repair work typically adds $500 to $1,500 to your project, bringing total preparation costs to $1,300 to $2,500 for a two-car garage.

Severe damage is less common but not unusual in older Ottawa homes, particularly those built before the 1980s when vapor barriers under garage slabs were not standard. Severe damage includes widespread deep spalling covering more than 30 percent of the floor, multiple large cracks with differential settlement where one side is higher than the other, crumbling or deteriorating concrete at the edges and near the garage door, or significant surface erosion from decades of salt exposure. Repairing this level of damage with individual patches becomes impractical, and a full resurfacing is usually the better approach.

A self-leveling concrete overlay or resurfacer is the standard solution for severely damaged floors. This is a polymer-modified cementitious product that is poured over the existing slab to create a new, smooth surface typically 6 to 12 millimetres thick. The existing floor needs to be sound structurally, meaning the concrete underneath is still solid even if the surface is rough, because the overlay bonds to it. A self-leveling overlay for a two-car garage costs $1,500 to $3,500 in Ottawa, depending on the thickness needed and the amount of prep work required to get the existing surface ready to accept it.

In extreme cases where the concrete itself is structurally compromised, with deep frost heaves, large sections that have broken away, or areas where the concrete crumbles when you poke it, a full slab replacement may be necessary. This means breaking out the old concrete, re-grading the base, and pouring a new slab. A full garage slab replacement in Ottawa costs $4,000 to $8,000 for a two-car garage, including removal of the old concrete, base preparation, new concrete, and finishing. This is a major project typically done by a concrete contractor rather than a coating contractor.

Getting an Accurate Quote

The challenge with budgeting for floor repair is that the full extent of damage is often not apparent until preparation begins. Surface grinding can reveal hidden cracks, delaminated areas, and moisture issues that were not visible before. A good Ottawa contractor will inspect your floor carefully, test for moisture, and give you a range rather than a single number if they suspect hidden damage. Some contractors offer a flat-rate preparation and repair package that covers whatever they find, which can give you budget certainty.

When getting quotes, ask specifically what level of repair is included in the base price and what would trigger additional charges. Get the triggers and additional costs in writing. This prevents the uncomfortable situation where a contractor starts grinding your floor, discovers more damage than expected, and presents you with an unexpected upcharge mid-project. Most reputable Ottawa contractors are upfront about this because they have seen enough local garage floors to know that hidden damage is common, especially in homes more than 20 years old.

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Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• 613Bins
• RenoMotion Inc.
• The Granite shop
• The Fixer
• Renovo Construction