Spot repairs $200 to $600Lift and relay from $1,500Same stone back down
Interlock repair in Ottawa, fix the cause before you relay the stone
Interlock repair in Ottawa costs $200 to $600 to reset a few sunken or cracked pavers, and $1,500 to $5,000 to lift a settled area, correct the base and relay the same stone. Paving Experts Ottawa finds the cause of the settling first, so the repair holds.
Pavers lifted, numbered where the pattern needs it, and reused
Base washout traced back to the drainage that caused it
Edge restraint replaced where the field has spread
Polymeric sand joints refilled and set
Get an interlock repair quote
Tell us roughly how large the sunken or damaged area is.
Photos of the settled area help us give you a tighter range.
What is usually underneath a settled area
Interlock does not sink on its own. Something moved the material beneath it, and that something is still there until it is dealt with.
Base washout
Water running through or under the base carries fines out of it and leaves voids. Usually it is a downspout discharging onto the driveway, a failed swale, or roof runoff with nowhere else to go. The drainage gets fixed first or the void comes back.
Utility trench settlement
A trench cut across the driveway for a service line settles for years after it is backfilled if the fill was not compacted in lifts. The giveaway is a depression in a straight line rather than a dish shape.
Failed edge restraint
Once a restraint breaks or lifts, the outer course walks outward and the joints open right across the field. Interlock carries load by transferring it sideways, and a field that has spread has stopped doing that.
Edge restraint is cheap and it is why the field stays tight
Edge restraint replacement runs about $15 to $25 per linear foot, which makes it one of the least expensive items on any interlock quote and one of the most consequential. An interlock surface is not a rigid slab. It works by transferring load sideways from paver to paver through the sand joints, and that only happens while the whole field is squeezed together. The restraint along the perimeter is what does the squeezing. When a restraint corrodes, snaps or gets pushed out by frost, the outer course moves outward a few millimetres. The joints behind it open. Sand washes out of the open joints. Load transfer stops, individual units start rocking, and the field begins to ripple. By the time it is visible in the middle of the driveway, the cause has been sitting at the edge for a couple of seasons.
Frost heave, and where Ottawa winters are heading
Frost damage requires frost susceptible soil, freezing temperatures and available water together. Champlain Sea clay classifies as CH, high plasticity clay, the worst frost susceptibility category, and this city supplies the other two conditions every winter. Water rises toward the freezing front, forms ice lenses and heaves whatever sits above them, then on thaw the meltwater cannot drain quickly and the material underneath loses bearing capacity temporarily. That is why interlock moves in March rather than January. What is more, the City projects winter freeze-thaw cycling up 15 percent by the 2030s and 35 percent by the 2050s, with snow cover days falling from 115 to 72. Less insulating snow means more bare surface cycling across zero, so milder winters are harder on hardscape here, not easier. The base is the only one of the three conditions you can control, which is why a relay that does not correct drainage is a repair with a countdown on it.
1%Minimum swale grade under Ottawa's grading specification, and swales that flatten out are a standing cause of washout
65 to 85Sensitivity of Champlain Sea clay, the soil under much of the city
15% to 35%Projected rise in winter freeze-thaw cycling by the 2030s and the 2050s
115 to 72Projected fall in snow cover days, meaning less insulation over the hardscape
Our Process
How a lift and relay runs
1
Read the shape of the depression
A dish points at a void or soft subgrade. A straight line points at a trench. A slump at one edge points at a restraint that has let go. The shape tells us where to open it.
2
Lift and stack the pavers
Units come up by hand and get stacked in order where the pattern is directional or the colour run varies. Broken units are set aside to be matched or sourced.
3
Correct the base and the drainage
Open the base, find where the water went, fix the source if it is on the property, replace washed out or contaminated granular and compact in lifts back to grade.
4
Reset, sand and compact
Screed the bedding layer, reset the same stone, sweep polymeric sand into the joints, plate compact and wet the joints so the sand sets.
Before you accept an interlock repair price
A repair that is worth paying for opens the base, identifies what happened, and deals with it before anything goes back down.
Has anyone read the shape of the dip?
A dish points at a void or soft subgrade. A straight band across the driveway points at a utility trench that was backfilled without compacting in lifts. A slump at one edge points at a restraint that has let go.
Has the water been traced?
Base washout follows a water path, usually a downspout discharging onto the driveway, a silted or regraded swale, or roof valley runoff concentrating in one spot. If the source is not named, the void comes back.
Is the bedding layer being replaced or reused?
It should be removed, because it has been contaminated and consolidated. Fresh bedding sand is screeded at a uniform thickness and is not used to correct a base that is out of grade.
What is written on the quote?
Ask what happens if soft subgrade shows through and geotextile is needed. Any workmanship warranty is set out in your written quote, job by job.
Cleaning and sealing without wrecking the joints
Maintenance done badly is the fastest way to create the repair you were trying to avoid.
Pressure washing, carefully
At $1 to $2 per square foot it is a legitimate maintenance item and the fastest way to ruin a driveway if done wrong. A narrow tip held close strips polymeric sand out of a joint in seconds. Wide fan tip, distance, and a plan to re-sand afterwards.
Re-sanding is not optional
Joint sand replacement runs $3 to $5 per square foot. Joints that are visibly low, that grow weeds freely or that let a screwdriver push in easily are telling you the sand has gone and load transfer has stopped.
Sealing is optional
Interlock sealing runs $2 to $4 per square foot. It deepens the colour, makes spills easier to lift and helps stabilise the joints. It needs the surface genuinely dry, and it is not a substitute for sound joints or a sound base.
Interlock repair and maintenance prices
Ottawa area ranges. Lift and relay is priced by area and by how much base correction turns up once it is open.
Spot repair
$200 to $600
A handful of units reset to grade
Trip hazards levelled
Cracked or spalled pavers swapped out
Joints refilled in the worked area
Settled area lifted and the base corrected
Granular replaced and recompacted in lifts
Cause of the settlement identified and addressed
Same pavers reset in the original pattern
Polymeric sand joint replacement $3 to $5 per sq ft
Edge restraint replacement $15 to $25 per linear foot
Pressure washing $1 to $2 per sq ft
Interlock sealing $2 to $4 per sq ft
Most interlock repair calls name the symptom, not the cause
The most common interlock repair request in this city is some version of the same sentence: a section has sunk, can you lift it and put it back. The answer is yes, and on its own that is the wrong job.
Interlock does not settle because pavers get heavier. It settles because the material underneath them moved, compressed or washed away. Lift the stone, screed some fresh bedding sand into the dip, reset the pavers and the driveway looks perfect for a season or two. Then the same area sinks again, because the void under the base is still filling with water, or the trench is still consolidating, or the restraint is still broken. Sometimes the fix is a five minute conversation about a downspout. Sometimes it is a genuine drainage correction. Either way it is the difference between a repair and a cosmetic reset.
Inside an interlock repair relay, from lift to joint sand
The pavers come up by hand. Where the pattern is directional, where there is a colour run, or where units have worn differently, they are stacked in order so they can go back the way they came. Damaged units are set aside.
The bedding layer is removed rather than reused. Then the base gets opened where the problem is, washed out or mud-contaminated granular comes out, and if soft subgrade is showing through, geotextile goes in before clean stone does. Granular is placed and compacted in lifts back to grade, and the grade is set deliberately so water leaves the area instead of collecting in it again.
Then the same stone goes back down, polymeric sand is swept into the joints, the field is plate compacted with a protective pad, and the joints are wetted so the sand sets. Done properly, the repaired area disappears once the joint sand has weathered to match.
Any workmanship warranty is set out in your written quote, job by job. Call (343) 314-8525.
Interlock repair questions
What does it cost to fix a sunken interlock driveway?
Lifting and relaying a settled area generally runs $1,500 to $5,000 depending on the size and how much base correction is needed once it is open. A small spot repair or levelling a trip hazard is $200 to $600. Joint sand replacement across a whole driveway is $3 to $5 per square foot and edge restraint replacement is $15 to $25 per linear foot.
Why did only one section settle?
Because the cause is local. Base washout follows a water path, so the depression tends to sit where a downspout discharges or where a swale has failed. Trench settlement follows the trench. Edge failure starts at one edge. Frost movement concentrates where water collects. The shape and position of the dip usually narrows it down before anything gets lifted.
Can the same pavers be reused?
Almost always, and that is the point of the surface. Units come up undamaged, get stacked, and go back down in the same pattern after the base is corrected. Broken or badly spalled units get replaced individually. A relay done properly is invisible once the joint sand has weathered in.
What if my paver line has been discontinued?
It happens, and it is the one real complication. Manufacturers retire product lines, so an exact match for a driveway laid fifteen years ago may not be in production. The usual answers are sourcing surplus from a supplier or another site, pulling units from a low visibility area such as behind a gate to patch the visible area, or introducing a deliberate border or accent so the difference reads as a design choice rather than a repair.
How often does polymeric sand need replacing?
There is no fixed interval, and it depends on exposure, slope and how the driveway is cleaned. Joints that are visibly low, that grow weeds freely or that let a screwdriver push in easily are telling you the sand has gone. Pressure washing is the usual culprit for premature loss, because a narrow tip held close will strip a joint in seconds.
Get the settlement diagnosed, not just covered up
We look at the shape of the dip, find the water and quote the repair that keeps it from coming back.
