Interlock cost per square foot is the installed price divided by the area, but no single number fits every job. Base depth, removal of the old surface, the paver you choose, the pattern, the number of cuts and the edging all move the price. A driveway needs a deeper base than a patio, so compare written quotes by scope before you compare by rate.
How interlock cost per square foot is worked out
Contractors quote interlock by the project, then you divide by the area to get a rate. The maths is simple. Measure the length and width, multiply, and divide the total installed price by that area. A driveway 6 m wide and 9 m long is 54 square metres, about 581 square feet. For an L-shape or a curve, split the space into rectangles and add them up.
The catch is that a rate only helps when every quote covers the same work. One contractor may include excavation to a full driveway base, hauling the old asphalt and edge restraint. Another may leave all three out and still look cheaper per square foot. The number on a quote tells you less than the line items behind it.
Quotes come in two forms. Some contractors give one rate for the finished surface, and others itemize excavation, base, pavers and labour. Ask for the itemized form, because it shows where the money goes. This guide gives no dollar figures, because a fair price depends on your site and scope.
What sets the price of an interlock job
These are the main factors, roughly in order of how much they matter:
- Area and shape. Larger areas spread set-up work across more square feet. Curves, corners and small awkward areas add labour.
- Base depth. Driveways need a deeper compacted base than patios and walkways.
- Excavation and removal. Digging out soil, then breaking out and hauling off old asphalt, concrete or pavers.
- Paver choice. Concrete pavers or natural stone, and the size, thickness and finish.
- Pattern and cuts. Simple running bond or herringbone, borders, and how many cuts the layout needs.
- Edge restraint and joint sand. The parts that hold the surface together.
- Access. Whether machines can reach the site or the work must be done by hand.
- Drainage and grading. Slope away from the house, and any change needed to move water.
The next sections cover the ones that confuse people most.
Base depth and excavation: the part you cannot see
The pavers get the attention, but the base does the work. A proper job excavates the area, lays geotextile where the ground needs it, then builds a compacted granular base in layers. A bedding layer goes on top, then the pavers, edge restraint and polymeric sand in the joints.
Driveways need a deeper base because vehicles load the surface far more than feet do. A typical driveway base runs about 20 to 30 cm (8 to 12 inches). Patios and walkways need less. More depth means more digging, more stone and more machine time, which is why a driveway and a patio of the same size are not priced alike.
The base also explains most failures. Sunken or heaved pavers and spreading edges usually trace back to a thin base, poor compaction or water that was never moved away. Many of these are fixed by lifting and relaying the pavers on a corrected base, as our guide to the signs you need interlock service explains.
Ask each contractor to state the base depth, the stone used and whether geotextile is included. A quote that skips these lines may be cutting the part that decides how long the job lasts. Freeze-thaw cycles in this region are hard on a weak base.
Removing the old surface and preparing the site
Replacing an old driveway or patio costs more than paving bare ground, because the old surface must go first. Crews break out and haul away asphalt, concrete or worn pavers. Soil that is dug out also has to leave the site. These steps take labour, equipment and disposal, and a quote should list them.
Other prep can change the price too:
- Tight access. A narrow side yard may rule out machines, so more work goes by hand.
- Grade changes. The surface must slope away from the house. If it does not, the grade has to be corrected.
- Water. A downspout that empties onto the paving or a low spot that holds water should be fixed, not covered.
- Tree roots and buried items. Roots and old foundations slow digging.
Ask what happens if the crew finds soft ground or buried material once the old surface is up. A clear answer before work starts prevents a surprise later.
Pavers, patterns, cuts and edging
Once the base is set, the visible choices drive the rest of the price.
| Choice | Why it affects price | Ask |
|---|---|---|
| Paver line | Concrete pavers and natural stone differ in material and handling cost | Which line, size and thickness is in the quote? |
| Pattern | Herringbone, mixed sizes and borders mean more cutting and more time than a plain running bond | Is the border or banding included? |
| Cuts and curves | Each cut takes time and creates waste | How many cuts does the layout need? |
| Edge restraint | Keeps the pavers from spreading | What type, and is it along every edge? |
| Polymeric sand | Locks the joints and helps hold the pavers together | Is it included, and how is it applied? |
| Permeable pavers | Water soaks through the joints into an open-graded base, which changes the build | Does my site suit it? |
A simple pattern on a plain rectangle costs the least labour. A curved patio with a border and several colours costs the most. Choose the pavers and pattern you love, then decide where to simplify if the total is high. Simplifying the base is the wrong place to save.
Interlock installation in Kitchener-Waterloo: local rules that touch the price
If your driveway work reaches the street side, the city may need to be involved. This is true across Kitchener and nearby cities, and the details vary.
- Kitchener requires a permit for widening a driveway or altering the curb within the municipal right-of-way, and its zoning by-law sets the maximum driveway width. Kitchener also says a widened driveway must match the existing material or be resurfaced in one consistent material.
- Waterloo says only the city can approve and complete curb cuts. It also asks owners to call at least two weeks before paving so crews can locate and mark the water shut-off valve.
- Other cities have their own rules, so check with your municipality before you order a wider driveway.
Before any digging, underground utilities are marked through Ontario One Call, a free locate service. Add any city permit and the time it takes to your planning. Fees and waits belong to the city, and your contractor can tell you what applies. Our guide to choosing an interlock contractor covers other questions to ask.
How to compare interlock quotes line by line
Put the quotes side by side and check for the same scope. Use this list:
| Line item | What to confirm |
|---|---|
| Area | The square footage or metres measured, and how curves were handled |
| Removal | What comes out, how it is hauled and who disposes of it |
| Base | Depth, stone type and compaction in layers, and whether geotextile is included |
| Pavers | Line, colour, size, thickness and pattern |
| Edges and sand | Edge restraint type and polymeric sand |
| Drainage | Slope away from the house and where the water goes |
| Warranty | Workmanship terms in writing, plus the paver maker's own warranty |
Each job at D&D Exterior Finishing starts with a free written estimate that lists the scope, materials, colours and warranty terms before work starts. See the interlock installation service page for what we build. For budgeting a larger project, read our guide to budgeting for an exterior renovation.
Interlock questions homeowners ask
How long does interlocking last?
There is no single number. A surface built on a properly compacted base, with good drainage and edge restraint, can serve for many years, and pavers can be lifted and relaid if sections settle. Most failures trace to the base, not the pavers. Ask for the paver maker's warranty and your installer's workmanship terms in writing.
Does interlocking increase home value?
It can help curb appeal and a buyer's first impression, but there is no guaranteed payback. Condition, neighbourhood and quality of installation matter. A sunken or heaved interlock surface can hurt more than it helps. Our exterior renovation ROI guide compares projects before you decide.
What is interlocking pavers?
Interlocking pavers are concrete or natural stone units laid in a pattern on a compacted granular base and bedding layer, with sand in the joints and an edge restraint. The shapes lock against each other so the surface spreads loads. Interlock is used for driveways, patios, walkways, steps and pool decks.
Why do interlock quotes vary so much?
Quotes differ because the work does. Base depth, removal of the old surface, paver line, pattern, cuts, edging and drainage all vary. A low quote may leave out part of the base or the removal. Ask each contractor to itemize the scope so you compare the same job.
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D&D Exterior Finishing serves Kitchener, Waterloo, Cambridge, Guelph and the surrounding region.
Get a Free Exterior QuoteKey Takeaways
- Cost per square foot is the installed price divided by area, and it only helps if every quote covers the same scope.
- Base depth is the biggest hidden driver, and driveways need a deeper base than patios.
- Removal of the old surface, pavers, pattern, cuts and edging all move the total.
- Kitchener and Waterloo have rules for driveway widening and curb cuts, so check before you plan.
- Ask for written base depth, scope and warranty terms from every contractor.
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