Can a spalled concrete garage floor in Moncton be resurfaced with an overlay or does the whole slab need to come out if the damage goes deeper than the surface?

A spalled garage floor can often be resurfaced with an overlay if the underlying slab is structurally sound, but the depth and extent of damage determines whether overlay or replacement is the right approach.

Concrete spalling in Moncton garages is extremely common due to our Maritime freeze-thaw cycles, road salt tracked in on vehicles, and the fact that many older garage floors were poured without air entrainment. The key question is whether the spalling is cosmetic surface damage or indicates deeper structural problems.

Surface spalling (up to 1/4 inch deep, affecting less than 30% of the floor area) can typically be addressed with a concrete overlay system. Modern polymer-modified overlays bond well to properly prepared concrete and can restore both appearance and durability. The existing slab must be structurally sound with no major cracks, settlement, or heaving. Professional preparation involves grinding off all loose material, acid etching or shot blasting to create a rough profile, and applying a bonding agent before the overlay.

Deep spalling (over 1/2 inch deep, widespread across the floor, or accompanied by structural cracks) usually indicates the original concrete has been compromised by freeze-thaw damage throughout its thickness. In these cases, overlay systems may fail within a few years as the deterioration continues beneath the new surface. Full slab replacement becomes the more cost-effective long-term solution.

The age and construction of your garage matters significantly. Garages built before 1980 in Moncton often used non-air-entrained concrete that's inherently vulnerable to our freeze-thaw cycles. If the original slab lacks proper reinforcement, has no vapor barrier underneath, or was poured too thin (under 4 inches), these deficiencies will eventually cause problems regardless of surface treatments.

Professional assessment is crucial because what appears to be surface spalling may indicate deeper issues like inadequate drainage, frost heave, or settlement. A concrete contractor can perform a sounding test (tapping with a hammer to detect hollow areas) and may recommend core sampling to evaluate the concrete throughout its thickness.

Cost considerations in the Moncton market: Professional concrete overlay systems run $4-8 per square foot, while full slab replacement costs $8-14 per square foot including removal and disposal. For a typical two-car garage (400-500 square feet), overlay might cost $2,000-4,000 versus $4,000-7,000 for complete replacement.

When to hire a professional: Any overlay work beyond small patch repairs requires professional assessment and installation. The surface preparation, bonding agent application, and overlay placement must be done correctly or the system will fail. Additionally, if your garage floor shows signs of settlement, major cracking, or water infiltration, these underlying issues must be addressed before any surface treatment.

Need help finding a concrete professional to assess your spalled garage floor? New Brunswick Concrete can match you with experienced contractors in the Moncton area who specialize in garage floor restoration and can recommend the most cost-effective approach for your specific situation.