How Long Does Interlock Last in Ontario?

Paver lifespan vs. install lifespan

A concrete interlocking paver manufactured by Unilock or Techo-Bloc is a dense, high-PSI concrete unit with a service life well over 30 years under normal residential use. The paver itself is rarely the failure point in Ontario. The failure point is almost always the install: the compacted base, the edge restraint, the joint sand, and the drainage under the surface. That is why ICPI-certified installs come with long workmanship warranties on top of the manufacturer's paver warranty, and why two patios laid with the same Unilock Beacon Hill Flagstone can look completely different at year 10.

What fails first on Ontario interlock

In the Golden Horseshoe, the most common patio and driveway failures we diagnose for homeowners in Hamilton, Burlington, and Oakville are:

• Base settlement. A 2-inch screenings base on clay subgrade will frost-heave, pump out fines, and leave pavers sitting in low spots. A 6-inch compacted 3/4-clear stone base will not.
• Edge restraint failure. Plastic edge restraints installed without 10-inch spikes driven into compacted base pop loose after one freeze-thaw season, and then the entire perimeter starts to spread.
• Joint sand loss. Regular masonry sand washes out in rain and under pressure washing. Polymeric sand locks the joints and resists weeds and insects.
• Subsurface water. Missing geotextile between subgrade and base, no drainage chimney, or a patio sloped toward the house all trap water where it causes heaving.

None of these are caused by the paver. All of them are caused by how the contractor prepared the site.

Paver warranty vs. workmanship warranty

Most homeowners do not realise that every interlock install carries two separate warranties:

• Manufacturer warranty (paver only): covers structural integrity of the paver itself. Unilock's residential lifetime warranty covers the paver, not the base or workmanship. Techo-Bloc offers similar coverage on its residential lines.
• Workmanship warranty (installer): covers base settlement, edge failure, and joint issues caused by the install. Seven Stones Landscape provides a 5-year workmanship warranty in writing on every interlock patio and driveway we build.

If a contractor cannot produce a written workmanship warranty, the paver warranty alone will not help you when the base settles in year three.

Base depth and jointing that survive freeze-thaw

Ontario's 60+ annual freeze-thaw cycles are what kills shortcuts. Every paver install we do for a patio, walkway, or driveway follows these minimums:

• Excavation: 10-12 inches on residential patios, 14+ inches on driveways to accommodate the 6-inch 3/4-clear base plus bedding and paver thickness.
• Geotextile: Mirafi 140N or equivalent non-woven geotextile between subgrade and base on all clay and silty-clay soils, which covers most of Hamilton, Burlington, Oakville, Milton, and Mississauga.
• Base: 6 inches of 3/4-clear stone, compacted in 2-inch lifts with a reversible-plate compactor.
• Bedding: 1 inch of HPB (high-performance bedding) or concrete sand, screeded level.
• Edge restraint: Aluminium or 3/8-inch fiberglass-reinforced PVC, spiked 10 inches into compacted base at 12-inch centres.
• Jointing: Polymeric sand swept into joints, activated per manufacturer directions, re-topped after first rain if needed.

These specs come straight from ICPI installation guidelines. Anything less is a shortcut that shows up in year 3 to 7.

Salt damage, efflorescence, and sealers

Road salt does not typically destroy Unilock or Techo-Bloc pavers the way it attacks cast concrete, because the pavers are manufactured at much higher PSI and lower water-to-cement ratios. However, salt does accelerate surface wear and encourages efflorescence in the first 1-2 seasons. Two things help:

• Use alternatives when you can. Calcium chloride is gentler than rock salt; sand provides traction with no corrosion risk.
• Seal at year 1-2. A penetrating sealer from the paver manufacturer resists staining and stabilises the polymeric sand. Re-seal every 3-5 years for high-traffic driveways.

For more on how salt behaves on adjacent concrete surfaces, see our guide on salt damage on Ontario concrete driveways.

Maintenance that extends lifespan

Interlock is low maintenance, not no maintenance. To keep a patio or driveway looking sharp and structurally tight well past 25 years:

• Sweep and rinse monthly during the growing season.
• Polymeric sand top-up every 3-5 years, or sooner if you see open joints.
• Spot weed control on any joint gaps before they expand.
• Check edges each spring - edge restraint popping up is the earliest sign of freeze-thaw damage and is cheap to fix early.
• Lift-and-relay the one or two pavers that settle after 10-15 years rather than leaving a trip hazard.

If you already see shifting pavers, open joints, or sunken areas, our interlock repair team diagnoses the base before doing any cosmetic work - because resetting pavers on a failed base is a one-season fix.

Restore vs. replace: how to tell

A properly built patio or driveway rarely needs full replacement. What it may need is a lift-and-relay, a base correction, and new polymeric sand. Here is how we triage jobs for homeowners in Hamilton, Burlington, and Oakville:

Symptom	Likely cause	Fix
Isolated sunken pavers	Local bedding settlement	Lift and relay affected section
Large dip across 1/4 of the patio	Base failure or drainage issue	Full lift, rebuild base, reinstall pavers
Pavers spreading at edge	Edge restraint failed	Replace edge restraint, re-sand joints
Open joints, weeds	Sand washout	Polymeric sand top-up
Paver surface crumbling	Rare - manufacturer defect	Claim under paver warranty

If the pavers themselves are in good shape, the smart path is almost always to save them and correct the base or edges. That is far cheaper than replacement and keeps the original colour and character of the install.

How to get a long-lasting install

Lifespan comes down to four things: excavation depth, base material, edge restraint, and jointing. Everything else follows from those. Ask any contractor you interview to specify - in writing - the base depth, whether geotextile is included, what edge restraint system they use, and whether polymeric sand is standard. If they cannot answer clearly, they are not installing to ICPI standards and the install will not last.

Seven Stones Landscape has been building ICPI-certified interlock patios and driveways across the Golden Horseshoe since 2013. Every project is backed by a 5-year workmanship warranty on top of the Unilock or Techo-Bloc paver warranty. If you want a patio or driveway that is still structurally tight in year 25, request a free on-site estimate and we will walk through exactly what goes under the surface on your property.