Updated August 2026
Interlock is built to be taken apart. That is the whole point of it, and it is the reason a sunken paver in Ottawa is usually a fixable problem rather than a write-off. A poured concrete slab that cracks stays cracked; a patch shows and the crack keeps moving. An interlock patio, walkway or driveway that settles can often be lifted, corrected underneath and put back down using the same stone. The harder question is which of those you are actually looking at. A dip near a downspout, a spreading edge along a walkway, and a driveway apron that has dropped an inch since spring are three different problems with three different answers, and only one of them is solved by re-sanding the joints. This guide walks through what fails, why Ottawa in particular causes it, how a proper repair is done, and how to tell when the honest answer is a rebuild rather than a repair.
What actually goes wrong with interlock in Ottawa
Most interlock problems come down to a short list, and almost all of them start below the surface rather than on it.
A settled or heaved section. One area of a patio, walkway or driveway apron sits lower or higher than the rest. Water pools there after rain, or a paver rocks underfoot. The stone is usually fine. The base under it is not.
Joints that have lost their sand. The sand between pavers is structural, not decorative. It is what locks the surface into a single interlocking field so that load spreads sideways instead of pressing straight down on one stone. Once it washes out, individual pavers start moving independently, edges start creeping, and weeds and ants find the gaps.
A spreading or dropping edge. The perimeter is where an interlock surface is weakest, because the outermost row has stone on only one side of it. When edge restraint fails, the field slowly widens and the joints open.
A driveway that has dropped more than the patio next to it. A driveway carries vehicle load and needs a thicker base than a patio does. Where a driveway was built to patio depth, it tends to show up first at the apron, where the weight lands.
A retaining wall that is bulging. This is the one to take seriously. A wall that leans or bows is usually telling you that water is trapped behind the face with nowhere to drain. It is a structural issue, not a cosmetic one.
Why Ottawa's freeze and thaw is usually the cause
Ottawa does not have one long freeze. It has a season of freezing and thawing, over and over, from late fall into spring. Water soaks into the ground and into every small gap in a surface. When it freezes it expands. When it thaws it drains. Each cycle nudges what sits above it.
Interlock handles that better than a rigid surface, because it is many individual pavers on a compacted base with sand-filled joints rather than one large piece. When the ground moves, the joints flex and the pavers move together. That is exactly why we build in it, and we set out the full comparison in our interlock versus poured concrete and asphalt guide.
But that flexibility only works if the layers underneath were built for it. A base that was not compacted in lifts, bedding sand that was never screeded level, or joints that were filled with ordinary sand instead of polymeric sand will all move under freeze and thaw, and they will keep moving every year. Water that is not managed is what feeds the damage. A downspout emptying onto a patio, a grade sloping back toward the house, or a base with nowhere to drain will produce the same settled section season after season, no matter how many times the top gets reset.
The tell that separates a surface problem from a base problem
If the same spot sinks again within a season or two of being reset, the base is the problem, not the stone. Repeatedly relaying the top of a failing base is the most common wasted spend in interlock repair. The fix is to open that section, correct and re-compact what is underneath, and deal with wherever the water is coming from.
How an interlock repair is actually done
The method is the same one we use when we build, run in reverse.
1. Lift the affected stones. The pavers come up and are set aside. In most cases the same stones go back down, which is why a proper repair does not leave a visible patch. Matching replacement pavers years after the original install is difficult, and colour lots shift, so keeping the original stone matters more than it sounds.
2. Correct and re-compact the base. This is the actual repair. The base gets brought back to the right depth and profile and compacted properly, and the slope is set so that water runs away from the house rather than pooling at a door.
3. Re-screed the bedding layer. A level bedding course is what stops the resettled pavers from rocking.
4. Reset the same stone. Back into the original pattern, tight to the neighbouring field.
5. Re-sand the joints with polymeric sand. This locks the surface back together. Where joints have washed out across a wider area than the repair itself, re-sanding the whole field is usually the right call, because a half-locked surface is not locked.
Because interlock is modular, we work on the affected area rather than tearing out the whole surface. That is the practical advantage it has over a slab that cannot be un-cracked.
Repair, relay or rebuild: how to tell which one you need
These are three different jobs and they cost three different amounts.
A repair is a localised fix: one dip, one rocking paver, one dropped step, one section of washed-out joint. The rest of the surface is sound.
A relay is lifting a whole area, correcting the base across it, and resetting the same stone. This is the right answer when the surface has settled unevenly in several places but the pavers themselves are still in good shape and the drainage can be corrected.
A rebuild is the honest answer when the base was never built for the load it carries, when the pavers are broken or spalling rather than just displaced, or when the grading sends water the wrong way and no amount of resetting the top will change that. Rebuilding a driveway that was built to patio depth is not upselling; relaying it every three years is.
We would rather tell you which of the three you are looking at before quoting than sell you the cheapest one twice.
| The job | What it involves | When it is the right answer |
|---|---|---|
| Repair | A localised fix: one dip, one rocking paver, one dropped step, one section of washed-out joint | The rest of the surface is sound |
| Relay | Lifting a whole area, correcting the base across it, and resetting the same stone | The surface has settled unevenly in several places, but the pavers are still in good shape and the drainage can be corrected |
| Rebuild | Taking the surface back to a base built for the load it actually carries | The base was never built for that load, the pavers are broken or spalling rather than just displaced, or the grading sends water the wrong way |
What does interlock repair cost in Ottawa?
We do not publish an interlock price list, and we are straight about why. The number depends on how much area is affected, whether the base has to be corrected or rebuilt, whether the drainage that caused the problem has to be dealt with as well, and how easily a machine can reach the yard. A figure given over the phone before any of that is known is a guess, and guesses are what turn into a bigger bill later.
We look at the surface, tell you whether it is a repair, a relay or a rebuild, and give you one project-specific price against that.
Getting your interlock looked at
Ottawa Decking Solutions builds and repairs interlock patios, walkways, driveways, steps and retaining walls in Techo-Bloc and Permacon stone, across Ottawa, Kanata, Barrhaven, Orleans, Nepean, Stittsville, Gloucester, Findlay Creek, Vanier, Manotick and Gatineau. We are family-owned and locally owned, licensed and insured, and we back our work with a written workmanship warranty set out in your project agreement.
Every project we take on is designed in 3D and AutoCAD before a single board is cut, so you approve the exact result and the price together. If the work needs a City of Ottawa permit, we prepare the drawings and the bylaw setbacks as part of the job. Financing is available through our third-party partner iFinance if it helps to spread the cost.
Call (613) 902-6137 or email info@ottawadeckingsolutions.ca to have your interlock looked at. If a deck is part of the same yard, we build those too, as an Ottawa deck builder.
Common questions
How much is interlock repair in Ottawa?
It depends on how much area is affected and, more importantly, on whether the base underneath has to be corrected or rebuilt. A localised repair, a full relay of an area, and a rebuild of a surface whose base was never right are three different jobs. We do not publish a price list, because a number given before anyone has looked at the base, the drainage and the access is a guess. We look at the surface, tell you which of the three you are actually looking at, and price that.
Can a sunken interlock patio be repaired without redoing the whole thing?
Usually, yes. Interlock is modular, so we can work on the affected area rather than tearing out the whole surface. We lift the affected stones, correct and re-compact the base underneath, reset the same pavers and re-sand the joints with polymeric sand. Using the original stone is what stops the repair from showing as a patch.
What is the typical lifespan of interlock?
There is no single answer, because the surface lasts as long as what is underneath it. A field set on a properly compacted base, with the slope designed to move water away and the joints kept sanded, holds up for a long time in Ottawa and can be repaired in place when a section moves. A field set on a base that was rushed will keep settling however many times the top is reset. The base, the drainage and the joint sand are the three things that decide it.
How do I redo faded or tired-looking interlock?
The first thing to establish is whether the problem is the surface or the structure. If pavers are rocking, dipping or spreading, that is a base and joint issue and it needs to be fixed before anything cosmetic is worth doing. Resetting the affected area on a corrected base and re-sanding the joints with polymeric sand brings a tired surface back into line.
Do you repair interlock driveways as well as patios?
Yes. Patios, walkways, driveways, steps and retaining walls. A driveway is built on a thicker base than a patio because it has to carry vehicle load, so a dropped driveway apron is often a sign the base was not built deep enough for what is parked on it. That distinction changes whether the right answer is a relay or a rebuild.