Interlock installation in Markham and nearby

Most of a good interlock installation is buried. Whether a walkway or patio stays flat for years depends on how deep the ground was dug, what went back in, and how well it was compacted.

New interlock makes sense when the surface you have, or the lack of one, bugs you every day. Think of a cracked concrete front walk that catches the snow shovel, a muddy path worn across the lawn to the back gate, or a backyard where the chairs sink into the grass.

It also gives a clean line between lawn and beds, like the interlock border on our sod, edging and mulch project.

If your interlock has only sunk or cracked in a few spots, you probably don’t need new interlock. Interlock repair fixes those sections and usually costs far less than starting over.

Every interlock installation follows the same order:

1. We mark out the area and set the slope first. Unilock’s installation guide says every installation should slope away from the house.
2. Buried lines get marked before anyone digs. In Ontario a public utility locate is free and required by law, and the Ontario Dig Authority (formerly Ontario One Call) asks for at least five business days’ notice for a single-address job. Private lines, like gas to a barbecue or power to a shed, need a separate private locate.
3. We dig out sod, soil or the old surface and take it away.
4. Gravel goes in and is compacted with a plate compactor in layers of 2–3 inches, to the depth in the table below.
5. A 1-inch bed of coarse sand is screeded over the base, which already carries the slope. The Concrete Masonry & Hardscapes Association warns against using bedding sand to even out a bumpy base.
6. The pavers go down in your pattern with clean cuts along the edges, and edge restraints keep them from spreading.
7. We compact the surface and fill the joints with polymeric sand, then wet it so it sets. Techniseal’s data sheet asks for dry pavers, a day without rain and 48 hours above 0°C while it dries.

It depends on what the interlock carries. Typical figures from Unilock’s basic technical guide:

Scroll sideways to see the whole table.

Clay soil needs deeper digging than sandy soil. Unilock’s contractor guide to paver base is more cautious, at about 10–12 inches for patios and walkways and 14–16 inches for driveways, so treat the lower numbers as a minimum.

Our guide to what goes under interlock covers gravel types, bedding sand and fabric in more detail.

Size, base depth and access move the price the most, so two patios of the same size can be very different jobs. A driveway needs a much deeper base than a walkway, and a backyard patio where everything goes through a narrow side gate takes longer than a front walk beside the driveway.

Tearing out an old concrete slab or failed interlock adds work, and curves, borders and herringbone mean more cuts. If a driveway change involves the curb, the permit is part of the cost too. For published market ranges and how base depth shows up in the number, see how much interlock costs in the GTA.

Build while the ground isn’t frozen, which in Ontario usually means spring through fall, and settle the quote and design over the winter. Late-fall jobs depend on the forecast, because the joint sand needs two dry days above 0°C.

• Sweep it often and rinse it in spring. Our interlock cleaning guide covers washing it without blasting out the joints.
• Pull weeds while they’re small, and keep downspouts from emptying onto the pavers.
• Top up or redo the joints when they get low. The polymeric sand guide explains when.
• Sealing is optional. Read whether you should seal your interlock first.

A small walkway or paver border is a fair DIY project if you’re patient and can rent a plate compactor. A patio or driveway means hauling a lot of soil and compacting a lot of gravel, and mistakes in the base or slope often only show after the first winter.

Our guide on why interlock sinks explains what goes wrong.

We’re based in Markham and work across nearby areas including Richmond Hill, Vaughan and Scarborough. The easiest start is to text a few photos of the area to (437) 684-2535 with your street or postal code. We’ll come out, measure and give you a free quote.

• A cracked or heaving concrete walkway you'd rather replace than patch
• A muddy path worn across the lawn where everyone actually walks
• A backyard with no flat, dry place to put a table and chairs
• Patio slabs on sand that have shifted, rocked and spread over the years
• Lawn and garden beds running into each other with no clean edge
• An old interlock surface that has failed in so many places that repairs no longer make sense