Exposed Aggregate Concrete: The Complete Guide for Toronto Homes and Commercial Projects
Quick answer: Exposed aggregate concrete is concrete where the top layer of cement paste is removed after placement, revealing the natural stone (aggregate) underneath. The result is a textured, slip-resistant, decorative surface that's popular for driveways, patios, walkways, and pool decks across Toronto and the GTA. Bathurst Mobile Ready Mix supplies and delivers fresh concrete for exposed aggregate projects, mixed on site so your crew gets the right amount at the right time.
Exposed aggregate is one of the most searched decorative concrete finishes in Ontario, and for good reason. It looks high-end, it handles our freeze-thaw winters well when it's built correctly, and it gives better traction than a smooth finish. Below, we answer the questions homeowners, contractors, and property managers ask most.
What Is Exposed Aggregate Concrete?
Every concrete mix contains aggregate: stone and sand bound together by cement paste. On a standard broom or trowel finish, that paste covers the stone. With exposed aggregate, the finisher removes a thin layer of surface paste so the tops of the stones show through.
The finished surface shows the colour, shape, and texture of the stone itself. Depending on the aggregate used, you can get a look that ranges from smooth, rounded river-rock tones to a sharper, more angular granite or limestone finish.
How Is Exposed Aggregate Concrete Made?
There are three common methods. Your contractor will choose based on the look you want and the size of the job.
Surface retarder and wash (most common). The concrete is placed, screeded, and floated. A surface retarder is sprayed on top, which slows the set of the top layer only. Once the slab below has hardened enough, the crew washes or pressure-washes off the soft surface paste to reveal the stone. Timing follows the retarder manufacturer's directions.
Seeding. Decorative stone is broadcast by hand onto the fresh surface and pressed in, then exposed by washing. This lets you use a premium decorative stone on top while the mix below stays standard.
Grinding or sandblasting. The surface is mechanically abraded after hardening. Grinding produces a smooth, polished look and is used more often indoors or on commercial floors.
What right looks like: concrete placed on a properly compacted base, finished promptly, exposed at the right moment, cured for at least 7 days, then sealed.
Is Exposed Aggregate Good for Ontario Winters?
Yes, when the mix and the installation are right. Exterior flatwork in Ontario is exposed to freeze-thaw cycles and de-icing salts, so the concrete needs to be built for it. The Cement Association of Canada's residential flatwork guidance calls for:
32 MPa specified compressive strength (Class C-2 exposure)
5% to 8% air entrainment (when using 20 mm aggregate), which gives water room to expand when it freezes
At least 7 days of curing with adequate moisture and temperatures above 10°C
Avoiding de-icing chemicals, especially in the first winter, using sand or fine grit instead
Routine sealing, typically every 1 to 2 years, depending on exposure and the product used
Want to understand what that 32 MPa number means? Read our guide: Understanding Concrete Mix Strengths: MPa Explained.
Where Is Exposed Aggregate Concrete Used?
Residential:
Driveways
Front walkways and steps
Patios and backyard entertaining areas
Pool decks (the texture helps with grip around wet areas)
Garden paths and borders
Commercial:
Plaza and storefront walkways
Condo and townhouse common areas
Parking lot islands and curbs
School, park, and municipal paths
Restaurant patios
Exposed Aggregate vs. Stamped Concrete vs. Broom Finish
Look: Exposed Aggregate: Natural stone texture; Stamped Concrete: Patterned (brick, slate, stone); Broom Finish: Plain, lined texture
Traction: Exposed Aggregate: Excellent; Stamped Concrete: Can be slippery when sealed and wet; Broom Finish: Good
Shows dirt and wear: Exposed Aggregate: Hides it well; Stamped Concrete: Colour can fade at high-traffic spots; Broom Finish: Shows stains more
Maintenance: Exposed Aggregate: Reseal every 1 to 2 years; Stamped Concrete: Reseal regularly, recolour over time; Broom Finish: Seal recommended
Best for: Exposed Aggregate: Driveways, pool decks, walkways; Stamped Concrete: Patios, feature areas; Broom Finish: Budget-friendly utility slabs
What Are the Pros and Cons of Exposed Aggregate?
Pros
Slip-resistant texture, wet or dry
Hides tire marks, dirt, and minor stains better than smooth concrete
Upscale, natural look that adds curb appeal
Long-lasting when built with the right mix and sealed on schedule
Wide choice of stone colours and sizes
Cons
Timing during installation matters. Expose too early and stones loosen; too late and paste won't wash off
Rougher texture than a smooth trowel finish (not ideal for barefoot play areas with large aggregate)
Needs periodic resealing
Repairs are harder to colour-match than plain concrete
How Much Does Exposed Aggregate Concrete Cost?
Pricing depends on the project, so we don't post a flat rate. The main factors are:
Total volume of concrete (area x thickness)
Type of aggregate and whether stone is seeded on top
Site access for the truck and crew
Base preparation and excavation required
Labour for finishing, washing, jointing, and sealing
Removal of an old driveway or slab
On the material side, one way to control cost is to avoid paying for concrete you don't use. Bathurst's volumetric trucks mix concrete fresh on site, so you pay only for what goes into your forms. Call 416-656-1937 for a quote on your project.
How Long Does Exposed Aggregate Concrete Last?
A properly installed, air-entrained exposed aggregate slab can last for decades. What shortens its life is almost always one of these: a weak or poorly compacted base, the wrong mix for exterior use, poor curing, salt use in the first winter, or skipped sealing. Get those right and the surface holds up to Toronto winters year after year.
How Do You Maintain Exposed Aggregate Concrete?
Seal it after the concrete has cured, following the sealer manufacturer's instructions, then reseal every 1 to 2 years
Skip de-icing salt in the first winter and use sand or grit instead
Clean it with a garden hose or low-pressure washer. High pressure held too close can loosen stones
Clear snow with a plastic shovel or blade rather than steel where possible
Remove oil spills quickly before they soak in
Why Fresh, On-Site Mixed Concrete Matters for Exposed Aggregate
Exposed aggregate is a timing-sensitive finish. Your crew needs concrete that arrives ready when they are, in the quantity they need, without sitting in a drum on the road.
Bathurst Mobile Ready Mix uses volumetric trucks that carry the raw materials separately and mix concrete fresh at your site. That means:
Fresh concrete, mixed when your crew is ready to place it
You pay only for what you use, with no guessing on volume
Flexibility on the day if the job needs a little more or a little less
We supply and deliver concrete for residential and commercial projects across Toronto, Scarborough, Markham, Aurora, Oshawa, and the wider GTA.
Frequently Asked Questions About Exposed Aggregate Concrete
What is exposed aggregate concrete?
Exposed aggregate concrete is concrete with the top layer of cement paste removed to reveal the stone underneath, creating a textured, decorative, slip-resistant surface.
Is exposed aggregate concrete slippery?
No. The exposed stone gives it more grip than smooth or stamped concrete, which is why it's a popular choice for driveways, ramps, and pool decks.
Is exposed aggregate more expensive than regular concrete?
It usually costs more than a basic broom finish because of the extra finishing labour and any decorative stone. Final cost depends on the size of the job, the stone chosen, and site conditions.
How long after pouring can you wash exposed aggregate?
It depends on the surface retarder used and the weather. Follow the retarder manufacturer's instructions. Exposing too early can loosen stones, and waiting too long makes the paste hard to remove.
Does exposed aggregate concrete need to be sealed?
Sealing is strongly recommended in Ontario. The Cement Association of Canada recommends routine sealing of exterior flatwork, typically every 1 to 2 years, especially where de-icing salts are used.
Can you use salt on exposed aggregate concrete?
Avoid de-icing chemicals, especially during the first winter. Use sand or fine grit instead to protect the surface.
What strength of concrete is used for an exposed aggregate driveway?
Exterior flatwork in Ontario exposed to freeze-thaw and salts is typically specified at 32 MPa with 5% to 8% air entrainment (Class C-2).
Does Bathurst Ready Mix deliver concrete for exposed aggregate projects?
Yes. Bathurst Mobile Ready Mix supplies and delivers fresh, on-site mixed concrete for residential and commercial exposed aggregate projects across Toronto and the GTA. Call 416-656-1937 for a quote.
Can I get an exposed aggregate driveway in Toronto?
Yes. Exposed aggregate is a popular driveway finish across Toronto and the GTA because it offers strong traction and hides wear. For exterior flatwork, the mix is typically specified at 32 MPa with 5% to 8% air entrainment to handle freeze-thaw cycles.
Can you put exposed aggregate over an old concrete driveway?
Most exposed aggregate driveways are poured new over a properly prepared base. Some existing slabs can be overlaid, but a contractor should first assess the condition of the old concrete, since cracks and heaving underneath will show through.
When is the best time of year to pour exposed aggregate in Ontario?
Late spring through early fall is ideal, when temperatures stay reliably above 10°C for the first week of curing. Cooler-weather pours are possible with protection such as insulated blankets.
How do I clean exposed aggregate concrete?
Rinse it with a garden hose or a low-pressure washer and use a stiff brush for stubborn dirt. Avoid holding a high-pressure nozzle close to the surface, which can loosen stones. Treat oil stains quickly before they soak in.
Ready to Pour?
Planning an exposed aggregate driveway, patio, or commercial walkway? Get fresh concrete mixed on site, measured to the job, and delivered across the GTA.
Call 416-656-1937 or email admin@bathurstreadymix.ca for a quote.
Related reading: Understanding Concrete Mix Strengths: MPa Explained · How Much Concrete Do I Need? · How Long Does Concrete Take to Cure? · Top Trends in Modern Concrete Design for Homes in Toronto