The patio behind a townhouse in Toronto, Canada had started sinking in a few spots. The concrete wasn’t cracked badly, but it was uneven enough that walking on it felt off.
We didn’t replace the whole patio. We lifted the loose slabs, added some base material underneath, and reset them. It wasn’t perfectly level, and there are still tiny gaps, but it feels solid now.
It doesn’t look brand new, but it’s safer and more usable. For a low-budget fix, this was enough to make the patio functional again without spending thousands.
Great real-world case, Defizyn - glad you flagged the lift-and-relevel approach. Adding a few Toronto-specific notes for homeowners reading this in spring 2026:
The reason individual slabs sink on GTA patios is almost always the same thing: the original base was laid too shallow, or the bedding course washed out through a joint. In our climate you generally want a minimum 8-12" of compacted 3/4" crusher run under flagstone and pavers, with a 1" bedding layer of HPB or coarse sand on top. Anything less and the frost-thaw cycle will pump slabs out of plane within 2-3 winters.
Two follow-up tips:
Before re-setting, check drainage slope - you want at least 1/4" per foot away from the house. If water is pooling at the low spot, no amount of relevel will hold.
Seal the joints with polymeric sand rated for northern climates (Techniseal HP NextGel or SEK ProJoint Max both work). Stops weeds and slows bedding washout.
Good write-up on a problem we see constantly in the GTA, especially on townhouse patios and older interlocked driveways. Resetting the slabs and adding base material is the right call for a low-budget fix, and your result sounds solid.
One thing worth knowing for next time — or for anyone reading this dealing with the same issue: the reason these slabs sink in the first place is almost always the base, not the slabs themselves. In Toronto’s climate, the freeze-thaw cycle is brutal on anything that holds moisture below grade. If the original install used only a thin layer of sand without a compacted granular base underneath, water works into it all winter, freezes, expands, and slowly heaves or erodes the support.
The fix that actually holds long-term has a few layers. You want at least 6 to 8 inches of compacted Granular A or crusher run as your base, then a 1-inch bedding layer of coarse sand on top, and then the slabs. When you lift and reset, it is also worth checking whether water is pooling anywhere nearby — downspout discharge, a low garden bed, or even a neighbour’s lot grading that sends runoff toward the patio. You can reset perfectly and still get movement in two winters if the drainage is working against you.
For a townhouse, the other thing to check is where the water goes when it runs off the patio. If it is heading toward the foundation rather than away, that is a bigger conversation.
Your fix sounds like it bought you a good few years. If the movement comes back in the same spots next spring, that is usually a sign the sub-base needs a more thorough redo. Happy to walk through what that looks like if it becomes relevant.
