Concrete Repair & Restoration in Toronto, ON - Crack Stitching & Slab Professionals

What is Concrete Repair & Restoration?

A coating is only as good as the slab under it. Cracks that move, spalls that haven’t been patched, and slabs that are out of plane are the most common reasons epoxy floors fail - and most contractors skip this step to keep the quote low.

We don’t. Every coating quote includes the substrate repair the slab actually needs, so the floor we install lasts the full warranty. It’s why we’re trusted as Toronto’s full-spectrum epoxy flooring contractor - the prep is never an afterthought. Concrete repair is also a stand-alone service for owners who want raw concrete restored without a coating system on top, and it’s the first step in most epoxy floor repair and recoat jobs.

What’s Included

• Visual and tactile damage assessment
• Crack stitching with carbon fiber staples
• Rapid-set polyurea crack filling
• Epoxy mortar patches for spalls and corners
• Self-levelling underlayment for uneven slabs
• High-spot milling and expansion-joint detailing
• Final surface profile prep ready for coating
• Documented before/after for warranty

Fixing Cracked and Spalled Concrete Before Coating

Cracked and spalled concrete is not just an aesthetic problem in the GTA - it is a direct threat to coating adhesion and long-term performance. Concrete surface profile standards set by ASTM International (specifically ASTM D4259 and the CSP scale developed by the International Concrete Repair Institute) define how rough a surface must be for a coating to bond correctly. A spall or active crack disrupts that profile and creates a point of mechanical stress where coatings will lift within months, particularly in unheated garages in Scarborough or Etobicoke where January slab temperatures can drop below -15 degrees Celsius while the coating above it contracts at a different rate.

The repair sequence for cracked slabs starts with classifying the crack: dormant hairline cracks (under 1 mm wide) are ground open slightly with a crack chaser blade and filled with a rapid-set semi-rigid polyurea. Active cracks - ones that show measurable movement across seasons - require mechanical stitching with carbon fiber staples set 6 to 10 inches apart perpendicular to the crack axis, followed by a flexible polyurea fill. The staple pattern follows guidelines from the ICRI Technical Guideline 310.3 for structural crack repair. Skipping the staples and relying on fill alone means the crack re-opens under the next thermal cycle; we have re-done other contractors’ polyurea-only repairs in East York and Brampton garages after a single winter.

Spall repair follows a different process. Delaminated or hollow areas must be fully removed - typically with a cold chisel or small rotary hammer - back to sound substrate before patching. Shallow spalls up to 25 mm deep are rebuilt with a two-part epoxy mortar compound at roughly 100 percent solids, which bonds directly to the surrounding concrete without a separate bonding agent. Deeper structural spalls, more common in post-war industrial buildings around Scarborough’s industrial corridors along Birchmount Road, may require a cementitious polymer-modified repair mortar that is applied in lifts to avoid shrinkage cracking. Either way, the patched area must achieve a CSP 3 to CSP 5 profile before any primer or basecoat is applied.

A spall repair job on a 600-square-foot commercial floor in the GTA typically runs $800 to $2,200 CAD depending on spall depth and total affected area. That number is dwarfed by the cost of stripping and recoating a failed floor two years later - a job that costs $4 to $7 per square foot on top of whatever the original coating cost. Doing the substrate work correctly the first time is the only financially sound option.

Self-Levelling and Substrate Repair: When Your Slab Needs It

Not every concrete problem is a crack. A significant portion of GTA residential and light-commercial slabs - particularly poured-in-place basement floors from the 1950s through 1980s in areas like East York and Pickering - have out-of-plane surfaces from differential settlement, heave, or simply inconsistent original flatwork. A floor that varies by 10 mm or more across a 3-metre straightedge is not suitable for most broadcast flake or metallic epoxy systems, which telegraph surface irregularities directly to the finished surface.

The standard correction method is a cementitious self-levelling underlayment (SLU) poured to fill low spots and bring the slab within acceptable tolerances before coating. A quality SLU product flows to a feathered edge at 1-2 mm and can be built up to 50 mm in a single pour, depending on the formulation. Compressive strengths in the 25-35 MPa range (referenced in CSA A23.1 for normal-density concrete) are typical for polymer-modified SLU products after a 24-hour cure, making them strong enough to receive a full epoxy or polyaspartic coating system. The floor must be primed with a penetrating epoxy primer before the SLU is poured to ensure bond and prevent the slab from pulling moisture out of the underlayment too quickly - a common failure mode when crews skip the primer step to save time.

High spots are the opposite problem. A slab with prominent aggregate exposure, trowel ridges, or heaved areas from tree root pressure (a recurring issue in older residential neighbourhoods in Brampton and Etobicoke near mature street trees) requires grinding with a single-disc or planetary grinder equipped with diamond cup wheels. High spots above 5 mm typically need multiple grinding passes; very pronounced humps may require scarifying. Surface grinding also improves adhesion by opening the pores of the concrete, transitioning the surface from a closed CSP 1 to an open CSP 2 or CSP 3 profile suitable for a 100-percent-solids epoxy primer.

Expansion joints are a separate category that requires careful treatment. Filling expansion joints with a rigid epoxy material causes the coating to crack directly over the joint line as the slab moves seasonally - this is one of the most common complaints we hear from homeowners in Pickering who had a previous coating applied without proper joint treatment. The correct approach is to honour the joint: clean it out, apply a backer rod if the joint is deep, and fill with a flexible polyurea joint filler that remains pliable after cure. The coating is then applied over the cured flexible fill rather than bridging a rigid gap. This maintains the slab’s designed movement capacity and prevents the familiar dark crack line that reappears through the surface of otherwise intact floors. Expansion joint repair on a two-car garage floor typically adds $150 to $350 CAD to the project cost - a small line item that prevents a large cosmetic problem.

Concrete Repair on Commercial and Industrial Floors in the GTA

Commercial concrete repair carries higher stakes than residential work in two specific ways: the floor is usually in active service and cannot simply be closed for a week, and the loads it carries after repair are far heavier than a residential vehicle. Loading bays in Scarborough’s industrial corridor along Birchmount Road, for example, see forklifts at 8,000 to 12,000 kg gross vehicle weight, with hard polyurethane wheels that concentrate that load into a contact patch smaller than a boot heel. Any spall patch or crack fill that is not fully bonded to the surrounding substrate will shatter under that load within weeks.

For commercial slab repair, we use a two-part epoxy mortar system with a compressive strength above 70 MPa after cure - well above the 25-35 MPa compressive strength of standard ready-mix concrete. The higher strength means the patch is never the weak point. Epoxy mortar also bonds to the substrate without a cementitious bonding slurry, which eliminates one failure layer that weaker repair systems require. In food-processing facilities in Mississauga and Etobicoke where steam cleaning at high temperature is part of the daily routine, we specify a novolac epoxy mortar rated for continuous chemical exposure rather than a standard bisphenol-A epoxy, which can soften under prolonged hot water and caustic cleaner exposure.

Scheduling is a real constraint on commercial repair jobs. Most Markham and North York warehouse operators cannot take a production floor offline for two or three days. We work in sections - isolating 20 to 30 percent of the floor at a time, repairing and priming each section overnight, and returning it to service before closing off the adjacent zone. Rapid-set polyurea crack fillers cure to full vehicle load capacity in 30 to 60 minutes, which allows us to complete crack repair in one section and have forklifts back on it before the crew moves to the next bay. Epoxy mortar patches require a longer cure window - typically 4 to 6 hours to foot traffic and 12 to 24 hours to forklift load - so section sequencing is planned around the facility’s shift structure. We provide a repair sequencing plan in writing before work starts so the operations team can coordinate material and equipment movement without guessing when each zone will be ready.

Related Questions Toronto Homeowners Ask

How do I know if my garage floor cracks need stitching or just filling?

Cracks wider than 3 mm, cracks with visible vertical or horizontal displacement between the two sides, and any crack that has grown measurably over one or more winters should be stitched with carbon fiber staples before filling. Hairline cracks under 1 mm in an otherwise stable slab can be filled with a semi-rigid polyurea without stitching. If you are unsure, a contractor who skips an assessment and quotes fill-only on sight should be a red flag.

What does concrete spall repair cost in Toronto?

In the GTA, spall repair using a two-part epoxy mortar runs approximately $12 to $22 CAD per square foot of affected area for residential work, depending on depth and access. A typical two-car garage with moderate spalling across 15-20 percent of the slab might cost $600 to $1,400 CAD for the repair work alone, before any coating. Commercial floors with widespread industrial spalling are priced per square foot on a project basis.

Can self-levelling underlayment fix a sloped garage floor in Scarborough or Etobicoke?

Self-levelling underlayment corrects out-of-flat conditions (undulations, low spots, minor settlement) but is not designed to add significant cross-slope to a slab. If your garage floor slopes toward the door and you want to change that slope, the options are either a polymer-modified cementitious topping applied with screeds and trowelled to the target slope, or in severe cases, a structural fill. Most SLU products flow to level on their own, which is useful for correcting a sunken centre but not for redirecting drainage.

How long does a full concrete repair and recoat take for a two-car garage?

A two-car garage (roughly 400-500 sq ft) with moderate cracking and patching needs, followed by a full epoxy coating system, typically takes two days plus cure time. Day one covers crack preparation and stitching, epoxy mortar patching, and diamond grinding. Day two covers primer, broadcast basecoat, and topcoat. The floor is ready for light foot traffic 12-24 hours after the final coat, and ready for vehicle traffic at 72 hours. Projects requiring a self-levelling underlayment add one day for the pour and cure.

Does concrete repair before coating affect the warranty on the epoxy floor?

Yes - it protects it. Coating manufacturers and professional installers void warranties on systems applied over substrates that were not properly prepared. When we perform substrate repair as part of a coating installation, that repair work is documented in the project file and the coating warranty covers the entire installed system. Skipping substrate repair to save $300 on a $2,000 floor installation is how homeowners end up with a failed floor and no warranty claim to make.