Short answer
A concrete patio in southern Ontario should be sized for your furniture, sloped about 1 to 2 percent away from the house, poured on a compacted granular base and finished with a slip-resistant texture. A published Ontario price guide lists patios at roughly $10 to $30 per square foot depending on finish (an estimate, not a quote).
Planning a concrete patio
Patios are one of the most requested residential concrete jobs because they add usable outdoor space at a lower cost than a deck of similar size, and they need less ongoing maintenance than wood. Good planning avoids the most common regrets: a patio that is too small, one that drains toward the foundation, or one that heaves against the house.
- Size. Measure with furniture in place. As a general rule, a dining table for four to six people needs a patio about 12 feet across so chairs can be pulled out without leaving the slab.
- Slope. The surface should fall gently away from the house, commonly about 1 to 2 percent, which is about 1/8 to 1/4 inch per foot.
- Isolation joint at the house. A flexible joint between patio and foundation lets each move independently with frost.
- Drainage. Water should have somewhere to go that is not your neighbour's yard or your window well.
- Future plans. Think about a hot tub, fire table or pergola posts before the pour so loads and footings are planned.
Finish options
The finish changes the look, the slip resistance and the price. See our concrete finishes guide for a fuller comparison.
| Finish | Best for | Notes |
|---|---|---|
| Broom finish | Most backyard patios | Lowest cost, good traction when wet. |
| Exposed aggregate | Natural stone look, pool surrounds | Textured and slip resistant. See exposed aggregate. |
| Stamped and coloured | Matching a pattern or colour scheme | Higher cost and ongoing sealing. See stamped concrete. |
| Coloured broom finish | A budget way to add colour | Integral colour with a simple texture. |
How a patio is built to last
- Layout and excavation to the depth needed for base plus slab.
- Compacted granular base, commonly 4 inches or more, with drainage considered.
- Forms and reinforcement suited to the slab size and soil.
- Air-entrained exterior concrete appropriate for freeze-thaw. See the salt and frost damage guide.
- Control joints cut or tooled to guide cracking, placed to divide the slab into roughly square panels.
- Finishing, curing and sealing. A cured, sealed patio absorbs less water and salt.
Typical patio thickness is about 4 inches, but a contractor may recommend more if vehicles or heavy equipment will cross it.
Costs and permits
The HomeStars Ontario price guide (updated August 2026, Ottawa-based contractors) lists patios at about $10 to $30 per square foot, stamped concrete at about $12 to $30, and demolition at about $3 to $8 per square foot where an old patio must be removed. These are ESTIMATE ranges only.
A concrete patio at grade does not usually involve the same permit requirements as an attached deck, but zoning rules such as lot coverage and setbacks can still apply, and the City of London publishes guidance on decks and other structures. Check with the City before building something large or near a property line. A related cost guide covers what to expect on a quote.
Frequently asked questions
How thick should a concrete patio be?
About 4 inches over a compacted gravel base is typical for foot traffic and furniture. Heavier loads call for thicker concrete and more reinforcement.
Can I add a patio against my house?
Yes, but it should be sloped away from the foundation and separated from it by an isolation joint so frost movement does not push against the wall.
Does a concrete patio need a permit in London, Ontario?
It depends on height, attachment and the zoning of your lot. The City of London has published guidance on decks, but a concrete patio is not covered in detail there, so ask the City directly.
How long before I can use a new patio?
As general guidance, foot traffic after a day or two and furniture after about a week. Follow your contractor's written instructions.
Is a concrete patio slippery?
A broom or exposed aggregate finish gives good traction. Smooth troweled concrete and high-gloss sealers can be slippery when wet.
Can a patio be added later to a deck or pool?
Yes. A patio can wrap a pool or sit beside a deck, but the slopes, joints and drainage need to be planned together.