Interlock and concrete both build a patio that lasts for decades, but they fail the same way: a skipped base. Interlock paver patios set individual units over a compacted granular base, so a damaged section can be lifted and reset. Concrete is one poured slab, cleaner to look at but harder to repair invisibly once it cracks.
What Is an Interlock Patio?
An interlock patio is a surface built from individual concrete pavers, laid tight in a pattern over a prepared base. The pavers are not glued down. They hold position through friction, an edge restraint around the perimeter, and jointing sand swept between them.
The real job is underneath. We excavate to depth and lay a compacted granular base, deeper on clay soil and deeper again for anything that has to carry a vehicle. We add edge restraint to keep the field from spreading, then lock the joints with polymeric sand. Done right, the patio reads as a single clean surface. Done wrong, with a thin or poorly compacted base, that is exactly where interlock heaves and ruts through an Ontario winter.
What Is a Concrete Patio?
A concrete patio is one continuous poured slab. There are no joints between units, just the surface you choose at the pour: broom-finished for grip, stamped to mimic stone, or coloured into the mix. It looks monolithic and modern, and there is nothing to sweep sand into later.
For our climate the spec matters as much as the look. Exterior flatwork that sees freeze-thaw and de-icing salt should be air-entrained at 5 to 7 percent air, CSA Class C-2, around 32 MPa, with a low water-cement ratio. Those tiny air pockets give freezing water somewhere to expand instead of spalling the surface. Control joints, cut no more than 2.5 metres apart and about one quarter of the slab depth, decide where the concrete cracks so it does not crack where it wants to.
Key Differences
Both materials can give you a patio that outlives the mortgage. The differences show up in how they look, what they cost relative to each other, and how they behave when something goes wrong.
Look and design
Interlock wins on variety. You get many colours, shapes and patterns: herringbone, running bond, soldier-course borders, banding, and clean curves that follow a garden bed. Concrete is the opposite strength. It is one calm, monolithic surface. Broom, stamp or colour, you pick the finish at the pour, and it stays that way.
Cost level
As a relative comparison, a poured concrete slab usually sits at the lower end and a detailed interlock layout at the higher end, because pavers are more labour to set and pattern. But the gap narrows fast once you spec concrete correctly, with the right air-entrained mix and proper jointing. The cheapest version of either one is the one with no base, and that version is the most expensive in the long run.
Longevity and freeze-thaw
This is the part most homeowners get backwards. Neither material is inherently tougher in our winters. Both last for decades when the base is right and, for concrete, when the mix is right. Both fail early when the base is skipped. Freeze-thaw does not politely choose a loser. It finds whatever was rushed, lifts the pavers that sat on thin gravel, and scales the slab that was poured wet without air entrainment.
Repairs and maintenance
Here the two part ways. Pavers are individual units, so a heaved or stained section can be lifted out, the base re-levelled underneath, and the same pavers reset, with no seam across the rest of the patio. If you want a patio you can fix one section at a time, a properly built interlock paver patio gives you that option. Concrete is one surface, so a crack or a scaled patch is far harder to repair invisibly, and you cannot re-choose the colour after the pour. Maintenance on interlock means topping up joint sand now and then. Maintenance on concrete means sealing and keeping salt off it.
The Base Is What Actually Decides
If you take one thing from this, take this: the base prep determines whether either patio lasts, not the material on top. A beautiful paver pattern over uncompacted fill will rut. A 32 MPa slab poured on soft, ungraded ground will crack outside its joints. We excavate to proper depth, compact in lifts, and grade so water drains away from the house and never onto a neighbour. That grading is not optional, it is what keeps the whole assembly from sitting in water it can freeze and lift.
Permits and Locates in the Hamilton Area
For an at-grade patio, the paperwork is light. An at-grade interlock or paver patio generally needs no building permit, because it is landscaping. At-grade poured concrete flatwork generally needs no building permit either. That does not mean no rules. Both still have to respect lot-coverage, setback and grading requirements, and the water has to drain away from your foundation and not toward the property next door.
One step is required by law for both, and it is free: an Ontario One Call locate before anyone digs the base. Buried gas, hydro, water and communication lines get marked first. We book the locate as part of the job, on every patio, no exceptions.
Which Should You Choose?
Use this as a simple decision framework:
- Choose interlock if: you want pattern, colour, curves or a border, and you value being able to lift and reset one area later without redoing the whole patio.
- Choose concrete if: you want a clean monolithic surface, a broom or stamped finish, and the lower relative cost of a single pour, and you are comfortable that repairs are less seamless.
- Either way: spend on the base. Insist on proper excavation depth, compaction, edge restraint or control joints, and grading that moves water off the slab. That is the line between a patio that lasts decades and one that fails in a few winters.
Frequently Asked Questions
Does interlock or concrete last longer?
Neither has a built-in edge. Both last for decades when the base is compacted to depth and, for concrete, when the mix is air-entrained and properly jointed. Both fail early when the base is skipped. In Ontario freeze-thaw, the prep under the surface decides longevity far more than the material you chose.
Which is easier to repair?
Interlock, clearly. Pavers are individual units, so a heaved, cracked or stained section lifts out, the base gets re-levelled, and the same pavers go back with no seam across the patio. Concrete is one continuous slab, so a crack or scaled patch is hard to fix invisibly, and you cannot match the original colour after the pour.
Do pavers shift over time?
Properly built, they hold. Shifting comes from a thin base, missing edge restraint, or joints that lost their polymeric sand. With a compacted granular base set to the right depth, edge restraint around the field, and joints kept full, the pavers stay locked. If a small area ever moves, you reset that section, not the whole patio.
Building a Patio in the Hamilton Area? Let's Talk Base First.
Whether you lean interlock or concrete, the patio is only as good as the prep underneath it. The Hammer Construction is a Hamilton-based crew, licensed and insured. Get a free quote at our online estimator, call or text (647) 424-1148, or email hello@thehammer.construction