A sinking or uneven interlock driveway doesn't just look bad — it can create tripping hazards, drainage problems, and long-term damage to your property. In the Greater Toronto Area, where freeze-thaw cycles and heavy vehicle use make interlock issues especially common, addressing sinking pavers promptly prevents small problems from becoming expensive repairs. Across Richmond Hill, Aurora, Vaughan, and Markham, we see the same recurring causes behind sinking interlock, and the good news is that nearly all of them are fixable. This guide covers why interlock bricks sink, how to diagnose the specific cause, and the professional repair process that restores a level, durable surface. Whether you need a minor re-leveling or a full driveway restoration, our interlocking services team handles every scope of repair across York Region.
Why Interlock Bricks Sink
Interlock pavers sink for a few predictable reasons, and identifying the correct one determines the right repair. Understanding the cause also helps prevent the problem from recurring after the fix. Here are the three most common culprits we see on GTA driveways.
- Freeze-Thaw Cycles:Ontario's repeated freeze-thaw cycles are the number one cause of sinking pavers. Water seeps beneath the pavers, freezes and expands in winter, then thaws and settles unevenly. Over several seasons, this lifts and drops pavers, creating uneven surfaces. This is especially severe in areas with poor drainage.
- Inadequate Base Preparation:The most common installation error is cutting corners on the gravel base. A proper interlock driveway needs 6 to 12 inches of compacted HPB (high-performance bedding) or 3/4-inch crushed gravel. Insufficient base depth or poor compaction leads to rutting and settling under vehicle weight, especially in York Region's clay-heavy soils.
- Water Drainage Washout:Downspouts discharging directly onto interlock, or poor surface grading, wash out the bedding sand beneath the pavers. Over time, the sand erodes and the pavers above sink into the void. This is common along driveway edges and near downspouts.
Diagnosing the Problem: Which Cause Is It?
The pattern of sinking tells you the cause. If pavers are sinking in tire-track lines, the base is inadequate — vehicle weight is compacting it further over time. If pavers sink near downspouts or along edges, water washout is the culprit. If the entire driveway has settled evenly, the base was under-compacted from the start. If individual pavers pop up in winter and settle in spring, freeze-thaw is the primary driver. A professional assessment confirms the cause and determines whether a spot repair or a full reinstallation is needed. Our team inspects the base, drainage, and paver condition to recommend the most cost-effective fix.
The Professional Repair Process
Fixing sinking interlock properly means addressing the underlying cause, not just re-leveling the surface. A surface-only fix will sink again. Here's the professional process we follow on every interlock repair across York Region.
- Step 1 — Remove the affected pavers:We carefully lift the sunken pavers and set them aside, preserving them for reinstallation. The bedding sand beneath is removed to expose the base layer.
- Step 2 — Inspect and repair the base:We examine the gravel base for depth, compaction, and drainage. If the base is insufficient, we add and compact additional HPB gravel to the proper depth. This is the step that most DIY repairs skip — and why they fail again within a season.
- Step 3 — Re-level the bedding layer:Fresh bedding sand is screeded to a uniform depth, creating a flat surface for the pavers. Proper screeding ensures the reinstalled pavers sit perfectly level.
- Step 4 — Reinstall pavers and re-sand joints:The original pavers are re-laid in their pattern, and polymeric sand is swept into the joints and activated with water. Polymeric sand hardens in the joints, locking pavers in place and preventing weed growth and water infiltration.
- Step 5 — Compact and seal:A plate compactor settles the pavers into the bedding, and a sealant protects the surface and joints from future water penetration. For the full benefits, read our guide on the advantages of interlocking.
Preventing Future Sinking
Once your interlock is repaired, a few preventive measures keep it level for decades. Direct downspouts away from the driveway with extenders or underground drainage. Re-sand joints with polymeric sand every 2 to 3 years to keep joints locked and water-resistant. Avoid parking heavy vehicles in the same spot continuously, which can create ruts over time. And schedule periodic maintenance to catch minor settling before it becomes a major problem. A properly installed and maintained interlock driveway lasts 25 to 30 years or more — the key is quality installation and consistent upkeep.
DIY vs. Professional Repair: When to Call a Pro
Small, isolated sinking — a single paver or a small edge area — can sometimes be DIY-repaired by lifting, re-screeding, and re-laying. But any repair involving more than a few pavers, or any sinking caused by base failure, needs professional equipment and expertise. Without a plate compactor, proper base material, and polymeric sand, a DIY repair will settle again within months. Professional repair costs more upfront but lasts years; a failed DIY costs twice because you eventually hire a pro anyway. For driveways — where vehicle weight tests every repair — professional installation is the only reliable choice.
Get Your Driveway Back to Level
Sinking interlock is a progressive problem — it only gets worse with time and weather, and the longer you wait, the more extensive the repair becomes. If your driveway, walkway, or patio has sunken pavers, our interlocking specialists serving Richmond Hill, Aurora, Markham, and Vaughan can diagnose the cause and restore a level, durable surface. We handle everything from minor re-leveling to full driveway reinstallation, using proper base preparation and premium materials that prevent future sinking. Request a free estimate and let's get your interlock back to looking and performing like new.