Sealing Exposed Aggregate Concrete

Sealing exposed aggregate concrete protects the pebbled surface from stains, wear and water damage while deepening its colour. In the Greater Toronto Area, a good sealer helps the concrete survive freeze-thaw cycles, road salt and summer UV without popping the small stones loose. Applied on clean, dry concrete and re-applied on a schedule, sealing keeps a driveway, walkway or patio easier to clean and looking close to new for years.

What sealing does for exposed aggregate concrete

Exposed aggregate concrete is a poured slab with the top layer of cement paste washed away to reveal small stones, pebbles or crushed rock. That pebbled surface looks great and grips well, but it is also full of tiny pores and gaps. Water, salt and grime settle into those spaces.

Sealing fills or coats those pores. On a GTA driveway, that means less water soaking in before winter freezes, fewer salt stains in spring, and less dirt ground into the surface by foot and tire traffic. A sealed surface also beads water, so spills sit on top longer and rinse off more easily. The sealer can deepen the natural colour of the stone for a richer look. That protection matters most on surfaces that take the most abuse, such as driveways with vehicle traffic and walkways hit by snow shovels every winter.

Why GTA weather makes sealing important

Toronto-area weather is hard on exposed aggregate. In winter, water gets into the surface, freezes and expands. Repeated freeze-thaw cycles can crack the slab or pop individual stones out of the surface. Road salt and de-icer melt snow and ice, then get carried into the concrete, where they can cause scaling and a dull, worn look.

Spring brings heavy rain and, in many Scarborough and North York yards, clay soil that holds water. If water cannot drain away from the slab, it sits against the concrete longer and keeps it damp. Summer sun and UV then bake the surface, slowly fading the stone and drying out unprotected concrete. A sealer helps on every front: it reduces how much water and salt soak in, and a UV-resistant sealer slows fading.

How sealing is done properly

Proper sealing is mostly about preparation. The surface must be clean and fully dry before any sealer goes on. That means removing dirt, moss and weeds from joints, treating stains, and letting the concrete dry so the sealer can bond instead of trapping moisture underneath. Small cracks and loose stones are dealt with before sealing so the sealer has a sound surface to bond to.

Once the surface is ready, the sealer is applied in thin, even coats so it does not puddle or turn cloudy. The concrete needs time to cure before it is walked on and before vehicles return to a driveway. Weather matters too: sealing is best done in mild, dry conditions, not in direct summer heat or just before rain.

Penetrating sealers vs. film-forming sealers

Exposed aggregate can be sealed with two broad types of product, and the right choice depends on the look you want and the condition of the surface.

• Penetrating sealers soak into the concrete and protect from within. They keep the surface looking natural and matte and do not form a visible skin that can wear or peel.
• Film-forming sealers leave a coating on top. They can give a wet-look or satin finish and deepen colour, but they sit on the surface and may need more careful re-coating over time.
• Colour-enhancing sealers darken the stone and can restore a faded surface. Ask us whether this suits your surface before you commit to a colour change.

If your aggregate is part of a larger hardscape, our natural stone and pattern concrete cleaning and sealing service covers these surfaces. If you are thinking about changing the colour, read our guide to exposed aggregate concrete staining first.

How often to reseal exposed aggregate

Most GTA driveways and walkways need resealing every two to four years, but the timing depends on traffic, shade and how the surface is used. A shaded patio that is rarely used can go longer between coats, while a sunny driveway that holds salt every winter may need attention sooner.

You can tell a sealer is wearing out when water stops beading, the colour looks faded or chalky, or stains begin to soak in quickly. Resealing on a schedule is far less work than repairing cracked or pitted concrete later, and it is one of the simplest ways to get more life out of an exposed aggregate driveway or patio.

Frequently Asked Questions

Will sealing make my exposed aggregate slippery?

Most sealers keep the natural grip of the stone, and a film-forming sealer adds gloss without turning the surface into a smooth painted floor. If slip resistance matters to you, tell us and we will choose a finish that keeps good traction.

Can I seal exposed aggregate myself?

You can, but the result depends almost entirely on cleaning and drying the surface first, and on applying the product evenly. Uneven coats, trapped moisture or sealing over grime are the usual causes of a cloudy, patchy result. Many GTA homeowners prefer to have it done so the surface is properly prepped.

How long does sealing last?

On a Toronto-area driveway or walkway, a quality sealer typically lasts two to four years with normal use. Shade, drainage and how often the surface is cleaned all affect the timing.

Can exposed aggregate be stained a different colour?

In many cases, yes. Colour is a separate step from sealing, and the right approach depends on the age and condition of the concrete. Ask us whether it suits your surface.

Seal Tech Inc. serves Scarborough and the GTA. Call (416) 966-4200 for a free written quote, or contact us online and send photos with your request.