How Long Does Interlock Last in Ontario?

A properly installed interlock patio or driveway in Ontario should last 25 to 30 years with basic maintenance. Some installations last longer. Poorly installed interlock can start showing problems within two to five years — shifting, heaving, cracking joints, and water pooling where it shouldn't.

That gap between 3 years and 30 years comes down to one thing: base preparation.

Ontario's climate puts interlock through a particular kind of stress. The freeze-thaw cycle — where temperatures repeatedly dip below zero and climb back above it through the winter and shoulder seasons — causes the ground to expand and contract. Water gets into the base, freezes, expands, and pushes the pavers up. When it thaws, they settle back down, sometimes unevenly.

This happens every winter. A base that isn't deep enough, properly compacted, or built with the right drainage to move water away from the sub-base will fail faster because every freeze-thaw cycle is doing a little more damage.

In Durham Region specifically, the clay-heavy soil common in Courtice, Oshawa, and Whitby makes this worse. Clay retains water rather than draining it. If that water has nowhere to go, it sits under the base material through the cold months and accelerates movement.

The base is what you can't see once the job is done, which is also why it's where corners get cut.

A proper interlock base in Ontario typically involves excavating to a depth of 8 to 12 inches below the finished surface, depending on the application and whether it's a patio or a driveway carrying vehicle weight. That depth gets filled with compacted granular material in layers, with each layer compacted before the next goes on. A bedding layer of finer material goes on top, the pavers are set, and the joints are filled with polymeric sand that locks the stones together and resists weed growth.

Each of those steps matters. Skipping or shortcutting any of them reduces the lifespan of the finished product, sometimes dramatically.

A driveway needs a deeper base than a patio because it carries vehicle loads. An installation near a downspout or in a low-lying area needs drainage built into it because water management is part of the job. These aren't optional upgrades — they're part of doing the work correctly for the specific site.

The most common causes of interlock failure in Ontario are all related to the base:

Insufficient depth is the most frequent problem. A base that isn't deep enough doesn't give the compacted granular material enough room to do its job. When the ground moves, the pavers move with it.

Poor compaction is common in rushed installs. Each layer of granular material needs to be mechanically compacted before the next layer goes on. Skipping compaction leaves voids in the base that collapse over time.

No edge restraints means the pavers at the perimeter have nothing holding them in place. Over time they migrate outward, creating gaps and uneven surfaces.

Poor drainage means water sits in and under the base rather than moving away from it. This is the root cause of most freeze-thaw damage.

Using the wrong base material — including recycled materials that don't compact uniformly — creates an inconsistent base that settles unevenly.

A well-installed interlock surface needs relatively little maintenance, but it does need some.

Polymeric sand washes out of joints over time, particularly after heavy rain and through freeze-thaw cycles. Reapplying it every few years keeps joints tight, prevents weed establishment, and stops pavers from shifting. It's an easy and inexpensive task that has a significant impact on how long the installation holds up.

Sealing interlock is optional but extends the life of the surface and makes it easier to clean. If you seal, use a product designed for interlock specifically, not a general masonry sealer.

Addressing problems early matters. A single paver that's shifted or heaved is a sign that water is getting into the base somewhere. Left alone, the problem spreads. Resetting a few pavers and investigating the drainage issue that caused it is far less expensive than eventually having to redo a section.

Individual pavers can be reset and the base underneath them repaired without disturbing the rest of the installation — as long as the problem is caught early and is localized.

If a large section is heaving, if joints are opening up across a wide area, or if water is consistently pooling where it wasn't before, that's usually a sign of a base failure that requires more significant work. In those cases, pulling up the affected section, correcting the base and drainage, and relaying is the right approach.

Patchwork repairs on a failing base don't hold. The underlying problem needs to be fixed or the surface will continue to move.

Interlock is one of the most durable paving options available, and when it's installed properly it performs exactly as advertised for decades. The key is finding someone who takes the base seriously — who digs to the right depth, compacts properly, addresses drainage, and doesn't cut corners on the steps that are invisible once the stones go down.

Those are the jobs that last 25 years. The shortcuts are the ones that need to be redone in five.

T.A.P Landscaping installs interlock patios, walkways, and driveways across Courtice, Oshawa, Whitby, and Durham Region. If you're planning a new installation or dealing with an existing one that's starting to move, get in touch for a free assessment.