What happens if concrete is not properly prepared before epoxy application in Ottawa

Consequences of Poor Concrete Preparation Before Epoxy in Ottawa

If concrete is not properly prepared before epoxy application, the coating will fail — it is not a question of if, but when and how badly. In Ottawa's extreme climate, poor preparation accelerates failure dramatically compared to milder regions. What might last a year or two in a temperate climate often fails within weeks to months in an Ottawa garage subjected to freeze-thaw cycling, road salt, snowmelt, and temperature extremes.

The most common failure mode is delamination — the epoxy literally peels off the concrete in sheets or large flakes. This happens when the concrete surface was not mechanically profiled (diamond ground or shot blasted) to create a CSP 2 to CSP 3 texture. Without that rough profile, the epoxy has no mechanical grip on the surface. Smooth, untreated concrete gives epoxy nothing to grab onto, and the thermal expansion and contraction that Ottawa floors experience 50+ times per winter pries the coating loose. You will see the edges curl up first, then entire sections lift away as moisture and salt work underneath.

Hot tire pickup is another frequent result of inadequate prep. When warm tires from a vehicle sit on poorly bonded epoxy, the heat softens the coating slightly and the tire literally pulls the epoxy off the floor when you drive away, leaving bare concrete patches in every parking spot. This is especially common with DIY kits applied over unground concrete — the bond strength simply is not strong enough to resist the suction and heat of tires.

Bubbling and outgassing occur when moisture trapped in or below the concrete cannot escape through the coating. In Ottawa, where spring snowmelt drives moisture vapour up through basement and garage slabs at elevated rates, skipping a moisture test before coating is a recipe for disaster. The moisture pushes through the concrete, hits the impermeable epoxy layer, and creates blisters ranging from pinhead size to several inches across. Once bubbling starts, the only fix is to strip the entire coating and start over — an expensive lesson that typically costs $3 to $6 per square foot for removal alone, plus the full cost of re-coating.

Applying epoxy over oil-contaminated concrete that was not properly degreased causes adhesion failure in the contaminated zones. Ottawa garages accumulate oil drips, transmission fluid, and antifreeze over years, and these petroleum products soak into concrete pores. Even if the surface looks clean after a mop, the contamination below the surface prevents the epoxy from bonding. These spots show up as soft, discoloured patches that peel easily.

Coating over existing sealers or paint without removal creates a weak sandwich — the epoxy bonds to the old sealer, but the sealer is not bonded well to the concrete, so the entire system lifts off in layers. Applying epoxy when the floor or air temperature is below 10 degrees Celsius — easy to do in an unheated Ottawa garage from October through April — prevents proper chemical cross-linking, leaving the coating soft, chalky, and unable to resist abrasion or chemicals.

The financial impact is significant. A failed coating means you pay for the original installation (typically $2,500 to $7,000 for a two-car garage), then pay for removal ($1,200 to $3,600), and then pay again for a proper installation. Investing in thorough preparation the first time — typically $800 to $2,500 — is far less expensive than fixing a failure. When hiring a contractor, ask detailed questions about their preparation process and get a written scope of work. The Ottawa Construction Network directory at justynrookcontracting.com can connect you with flooring professionals who take preparation seriously.

---

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

• 613Bins
• RenoMotion Inc.
• The Next Reno
• Valcor Construction
• Grunt Work 4 Grunts