Interlock Maintenance Guide · 2026

How to Get Rid of Weeds Between Interlock Pavers Permanently: Ontario 2026 Guide

By Riaad, Owner & Project Manager · ICPI Certified Installer · Published 2026-06-11

The only permanent fix for weeds between interlock pavers is to remove the failed joint material, kill the established roots, and refill the joints with fresh polymeric sand. Vinegar, boiling water, salt, and torching only burn the tops off the weeds; the roots stay alive in the joint and regrow within 2 to 4 weeks. Done correctly, a polymeric sand restoration keeps a Hamilton or Burlington patio weed-free for 4 to 6 years, and it costs $2.00 to $3.50 per square foot professionally in 2026.

Mid-June is when the calls start. The patio looked fine in April, and now there is crabgrass in the driveway joints and dandelions along the patio edge. Here is what is actually happening, what does not work, and the process we use on weed-infested interlock across Hamilton, Burlington, Oakville, and Milton.

Why Do Weeds Keep Coming Back Between My Pavers?

The most common misconception we hear on site visits: "the weeds are pushing up from under the patio." Almost never true. A properly built interlock surface sits on 8 to 12 inches of compacted granular base. Nothing germinates down there and pushes through.

Roughly 95 percent of paver weeds work the other way: seeds from dandelion, crabgrass, spurge, and plantain blow in on the wind or get tracked in, land in the joints, and catch in whatever is sitting there. If the joint is filled with hard, intact polymeric sand, the seed has nothing to root into and washes away. If the joint sand has eroded, cracked, or was ordinary brick sand to begin with, the joint slowly fills with windblown dust and organic debris, and that quarter-inch of dirt is all a weed seed needs.

That is why weeds are a symptom, not the disease. The disease is failed joint sand. It is also why pulling weeds every weekend never ends: you are clearing the surface while leaving a perfect seed bed in place. Every joint you see weeds in today will sprout new ones from the seed bank already sitting in it.

Ontario's freeze-thaw makes this worse than most climates. Joint sand that lost its top few millimetres to last summer's pressure washing or this winter's plow gets pried open further every time trapped water freezes. By year 5 to 7, most interlock surfaces in the Hamilton-Halton area have enough joint loss for weeds to establish, which lines up with what we cover in our guide on how long interlock lasts in Ontario.

What Doesn't Work (and Why)?

Vinegar. Household 5 percent vinegar burns leaf tissue and makes the weed look dead by dinner. The root crown survives, and the weed is back in 2 to 4 weeks. Horticultural vinegar (20 percent) does more damage but still rarely kills taproot weeds like dandelion, and it etches concrete paver surfaces with repeated use.

Salt. Salt does kill roots, which is exactly the problem. It moves with runoff into your lawn and garden beds, persists in soil for years, and attacks the paver surface the same way road salt scales a concrete driveway. We see salt-burned paver faces on driveways where someone spent two summers "spot treating" joints.

Torching. A propane weed torch kills top growth fast and is satisfying to use. It does not reach the root, it can scorch paver faces, and it does nothing about the dirt-filled joint that grew the weed.

Pulling by hand. Fine as a stopgap, and better after rain when the soil is loose. But crabgrass and spurge snap off at the crown, and you are leaving the seed bed in place either way.

Landscape fabric. Homeowners sometimes ask us to "lift the patio and add fabric." Fabric under the base does nothing because the weeds never came from below. Money is far better spent on the joints.

What Is the Permanent Fix? The 4-Step Process

This is the same restoration sequence we run on every weed-infested interlock surface, whether it is a 200 sq ft walkway in Dundas or an 1,800 sq ft driveway in Oakville.

Step 1: Kill or pull the established weeds, roots included. For light infestation we hand-pull after watering. For heavy infestation we treat with an Ontario-compliant herbicide and wait 5 to 7 days so the root dies before cleanout. Ontario's cosmetic pesticide rules limit what is available at retail, so the practical DIY options are removal tools and approved bio-herbicides (iron-based products like Fiesta work on broadleaf weeds).

Step 2: Pressure-wash the joints clean. 2,500 to 3,000 PSI with a 25-degree fan tip, held about 12 inches off the surface, angled to drive the old sand, dirt, and root fragments out of the joints. The goal is a joint cleaned out to at least 1 inch deep, down to clean sand or the bedding layer. This is the step most DIY attempts skip, and it is the step that makes the fix permanent. New sand over old dirt fails in one season.

Step 3: Refill with polymeric sand, correctly. Surface must be bone-dry. We sweep Gator Supersand G2 (or Techniseal NextGel on pool surrounds) into the joints, compact, top up, blow the dust off the paver faces, then mist-activate with water. The polymers bind the sand into a hard but flexible joint that sheds windblown seed instead of catching it. Cure time and rain risk matter here; we covered the details in our polymeric sand cure time guide.

Step 4 (optional but worth it): Seal the surface. A joint-stabilizing sealer applied 60 to 90 days later locks the sand surface, slows erosion, and makes the next pressure wash gentler on the joints. It typically adds 1 to 2 years to the weed-free window.

Interlock paver patio with dining set in a townhome backyard

How Much Does It Cost to Fix in Hamilton, Burlington and Oakville in 2026?

Scope	2026 cost per sq ft	Typical 400 sq ft patio
Weed kill + clean only	$1.25 to $2.00	$500 to $800
Clean + full resand (the permanent fix)	$2.00 to $3.50	$800 to $1,400
Clean + resand + seal	$3.50 to $5.50	$1,400 to $2,200

Driveways land at the top of each range because of vehicle staging and the extra cure time before parking on the surface. The full pricing breakdown, polymeric sand brand comparison, and a real Aldershot case study are in our 2026 interlock cleaning and sealing cost guide.

Clean-only quotes look tempting, but understand what you are buying: a clean patio with empty joints. Empty joints refill with windblown dirt within weeks, and you are back to weeds by August. If the joints have failed, resanding is the part that makes it permanent.

Can I Do It Myself?

Yes, if the surface is under 300 sq ft, you own or can rent a 2,500 to 3,000 PSI pressure washer, and the forecast gives you 2 to 3 dry days. Budget $250 to $450 in materials for a 400 sq ft patio: 4 to 6 bags of quality polymeric sand at $35 to $45 each, weed treatment, and washer rental if needed.

The two DIY mistakes that waste the whole weekend: applying sand to a damp surface (it sticks to the paver faces and films over), and over-watering during activation (it washes the polymers out before they bind). Mist, never spray. And if your pavers are also sinking, heaving, or shifting underfoot, stop: that is a base problem, not a joint problem, and new sand will not hold. That situation calls for interlock repair rather than restoration.

How Do I Keep Weeds Out After the Fix?

Rinse, don't blast. A garden hose or low-pressure rinse each spring clears seed and debris before it settles in. Save the pressure washer for the next full restoration cycle.
Sweep or blow the surface monthly in summer. Seeds that never sit in a joint never germinate.
Spot top-up early. If you see a joint opening up or a single weed appearing, fix that joint that month. One weed in June is a colony by September because a single dandelion head carries about 150 seeds.
Watch the edges. Joints along lawn edges and garden beds fail first because soil and seed sit against them. Keep a clean cut edge between lawn and pavers.
Reseal on cycle. Every 3 to 5 years, per our interlock maintenance schedule.

When Are Weeds a Sign of a Bigger Problem?

Weeds plus any of the following usually means the surface needs more than resanding: pavers that rock underfoot, standing water after rain, joint lines that have gone wavy, or edges creeping outward. Those are base and edge-restraint failures, and sand is just the visible casualty. Moss in the joints points at a drainage or shade problem, since moss needs sustained moisture that a well-drained surface should not have. If that sounds like your patio, start with our uneven interlock page, or have us look at it; a restoration quote on a failing base wastes your money, and we will tell you which one you actually need. Either way, the team that handles our interlock patio and driveway work does both.

Frequently Asked Questions

Do weeds between pavers grow up from underneath the patio?

Almost never. Roughly 95 percent of paver weeds start as windblown seeds (dandelion, crabgrass, spurge, plantain) that land in the joints, catch in dirt and failed sand, and germinate downward. That is why landscape fabric under the base does nothing to stop them, and why the fix is in the joint itself: clean it out and refill it with properly cured polymeric sand so seeds have nowhere to root.

Does vinegar, salt, or boiling water permanently kill paver weeds?

No. Vinegar and boiling water burn off the top growth but rarely kill the full root, so most weeds regrow within 2 to 4 weeks. Salt does kill roots but it leaches into surrounding beds and lawn, stays in the soil for years, and accelerates paver surface scaling the same way road salt does. None of these address the real problem, which is failed joint sand. They are stopgaps, not fixes.

What is the permanent fix for weeds in interlock joints?

A four-step restoration: (1) kill or pull the established weeds including roots, (2) pressure-wash the joints at 2,500 to 3,000 PSI to blast out the old failed sand, dirt, and root fragments, (3) let the surface dry completely, then sweep fresh polymeric sand (Gator Supersand G2 or Techniseal NextGel) into the joints and mist-activate it, and (4) optionally seal the surface 60 to 90 days later. Properly cured polymeric sand hardens into a flexible joint that windblown seeds cannot root into, which keeps the surface weed-free for 4 to 6 years in Ontario conditions.

How much does it cost to fix weed-filled interlock joints in Hamilton, Burlington or Oakville in 2026?

In 2026, professional clean-plus-resand service across Hamilton, Burlington, Oakville and Milton runs $2.00 to $3.50 per square foot, which covers weed removal, pressure washing, joint cleanout, and new polymeric sand. Adding a 2-coat sealer brings it to $3.50 to $5.50 per square foot. A typical 400 sq ft weed-infested patio costs $800 to $1,400 to restore without sealing, or $1,400 to $2,200 with sealing. DIY materials for the same patio run $250 to $450 but take a full weekend and a proper pressure washer.

Will polymeric sand stop weeds forever?

Not forever, but for a long time. A correctly installed polymeric sand joint stays weed-resistant for 4 to 6 years in the Hamilton-Halton freeze-thaw climate before normal joint erosion opens small gaps where seeds can catch again. An annual rinse and a quick spot top-up of any eroding joints stretches that cycle. Compare that to vinegar or torching, which buy you 2 to 4 weeks.

When is the best time of year to resand paver joints in Ontario?

June through September. Polymeric sand needs the surface bone-dry on application day, temperatures above 10 C, and ideally 24 to 48 rain-free hours to cure. Ontario summer gives you the most reliable weather windows. Resanding in early summer also means you remove this season's weeds before they go to seed and multiply the problem for next year.

Tired of pulling the same weeds every weekend? We restore interlock across Hamilton, Burlington, Oakville, Milton, Mississauga, Ancaster, Dundas, Stoney Creek, and Waterdown. Free on-site assessment and a written quote. Get a free quote