Concrete Sealing

We use commercially specified sealer products — not the big-box store consumer-grade aerosols — and we match the product type to the specific application. A garage floor that sees hydraulic fluid and road salt needs a different sealer than a decorative exposed-aggregate patio that gets foot traffic and furniture. A stamped concrete patio benefits from a topical film-forming sealer that enhances colour; a plain grey driveway is better served by a penetrating silane-siloxane that doesn't change the appearance but drives water repellency deep into the matrix. We explain the options so you know what you're getting.

Penetrating sealers — silane, siloxane, and silane-siloxane blends — chemically bond within the concrete pore structure and repel water without changing the surface appearance. They don't create a film that can peel, bubble, or turn white under standing water. For plain grey driveways, sidewalks, and garage aprons, this is almost always the right choice: invisible protection with zero ongoing maintenance beyond reapplication every 3 to 5 years. They're particularly effective against chloride intrusion from road salt, which is a serious problem on London-area driveways given how aggressively salt gets used on municipal roads from November through March.

Topical film-forming sealers — acrylics, polyurethanes, and epoxies — sit on the surface and create a physical barrier. They can dramatically enhance colour on stamped concrete, exposed aggregate, and decorative poured slabs, adding a wet-look or satin sheen. The trade-off is that topical coatings require surface prep when reapplying (the old film often needs to be stripped or lightly abraded before recoating), and high-traffic areas like driveways will show wear patterns over time. For patios, pool decks, and decorative surfaces, the aesthetic benefit usually outweighs the extra maintenance.

Garage floors are a specialized case. They face a combination of point-loading from vehicle tyres, thermal shock from hot exhaust systems on cold concrete, chemical exposure from oils and brake fluid, and road salt dragged in on wheel wells. Standard acrylic sealers don't hold up to that load. For garage floors we typically recommend either a two-part water-based epoxy or, for clients who want same-day turnaround, a polyaspartic topcoat — which cures hard in two to three hours rather than the 24 to 48 hours epoxy requires.

Both systems are applied over a mechanically ground or acid-etched concrete surface to ensure adhesion. We check for moisture vapour transmission before coating — garage floors poured directly on grade in Ontario's clay-heavy soil often have upward moisture drive, and coating over a high-moisture slab without an appropriate primer leads to delamination within months. Getting that diagnosis right before the project starts is the difference between a floor that lasts 15 years and one that bubbles and peels by the following spring.

The water-drop test works on concrete the same way it works on decks: splash water on the surface. If it beads, the sealer is active. If it absorbs and darkens immediately, the sealing capacity is depleted. Visual signs that sealing is overdue include surface dusting (fine white powder rubbing off the slab surface), light pitting or scaling on the top 2 to 3 millimetres, and salt-staining that doesn't wash off. None of these indicate structural failure — they indicate surface deterioration that a timely sealing will halt before it progresses to cracking.

New concrete should be sealed after the initial cure — typically 28 days after pour. Many contractors seal driveways on the day of pour or the day after, which locks in bleed water and prevents full hydration. The 28-day rule is worth following. For previously sealed surfaces, the reapplication window depends on the product used: penetrating sealers on a busy driveway typically last 3 to 5 years in Ontario conditions; topical acrylics on a lightly trafficked patio may last 5 to 7 years. We're happy to assess existing sealer condition as part of a free estimate visit.