How much does concrete levelling with polyurethane foam injection cost for an uneven GTA basement floor?

Polyurethane foam injection for basement floor leveling in the GTA typically costs $8-$15 per square foot of treated area, with most residential basement projects ranging from $2,500-$8,000 depending on the severity of settlement and total square footage requiring treatment.

Polyurethane foam injection (also called poly lifting or foam jacking) is an effective solution for settling basement floors that have developed low spots, cracks, or uneven areas due to soil settlement beneath the concrete slab. This process involves drilling small holes (typically 5/8-inch diameter) through the concrete and injecting expanding polyurethane foam underneath to lift and level the slab back to its original position.

Why GTA Basement Floors Settle

Toronto's clay soil is particularly problematic for basement floor stability. The expansive clay throughout much of Scarborough, North York, Mississauga, and Brampton shrinks dramatically during dry periods and swells when saturated, creating voids beneath concrete slabs. Additionally, many GTA homes built in the 1950s-1980s have basement floors poured over poorly compacted fill or organic material that decomposes over decades, leaving hollow spaces that cause the concrete to crack and sink.

Spring thaw cycles compound the problem — as groundwater levels fluctuate seasonally, the soil beneath basement floors can wash away through foundation cracks or failed weeping tile systems. Homes near ravines or on sloped lots are particularly susceptible to soil movement and basement floor settlement.

Polyurethane vs. Traditional Mudjacking

Polyurethane foam injection has largely replaced traditional mudjacking (pumping concrete slurry) for basement floors in the GTA because the foam is lightweight, won't add stress to already compromised soil, and cures within 15 minutes. The injection holes are much smaller than mudjacking (5/8-inch vs. 2-inch holes), and the foam won't wash away if water infiltration occurs later. However, polyurethane costs roughly 50% more than mudjacking — expect $8-$15 per square foot for poly vs. $5-$10 for traditional mudjacking.

GTA Pricing Breakdown

• Minor settlement (1/4-inch to 1/2-inch low spots): $8-$10 per square foot
• Moderate settlement (1/2-inch to 1-inch): $10-$13 per square foot
• Severe settlement (over 1-inch or multiple areas): $13-$15 per square foot
• Minimum project cost: Most contractors have a $1,500-$2,500 minimum
• Crack repair: Additional $300-$600 per crack if structural crack sealing is needed

A typical 800-1,000 square foot basement with moderate settlement affecting 200-300 square feet usually costs $2,500-$4,500 for polyurethane leveling. Severe settlement affecting half the basement floor can reach $6,000-$8,000.

What's Included and Timeline

Professional poly lifting includes site assessment, drilling injection holes, foam injection, hole patching with concrete, and cleanup. The actual injection process takes 2-4 hours for most residential basements, and the foam cures within 15 minutes, so you can walk on the floor immediately. However, wait 24-48 hours before placing heavy furniture or equipment on treated areas.

When Poly Lifting Won't Work

Polyurethane injection cannot fix basement floors with extensive structural damage, floors that have settled more than 3-4 inches, or situations where the underlying soil has completely washed away. If your basement floor has large cracks with significant vertical displacement, or if water actively flows up through floor cracks, you likely need full floor replacement ($8-$15 per square foot) rather than lifting.

Important Considerations for GTA Basements

Before investing in floor leveling, address any water infiltration issues. If groundwater is washing away soil beneath your basement floor, lifting the concrete won't solve the underlying problem. Many GTA homes need interior drainage systems or sump pump upgrades before floor leveling makes sense long-term.

Also consider your renovation timeline — if you're planning to finish the basement within 1-2 years, poly lifting is an excellent investment to create a level surface for flooring. However, if the basement will remain unfinished indefinitely, you might live with minor settlement rather than spend $3,000-$5,000 on leveling.

When to Hire a Professional

Polyurethane injection requires specialized equipment and experience to achieve proper lift without over-injecting and cracking the slab. This is definitely professional work — the foam expands with tremendous force and improper injection can cause more damage than the original settlement.

Need help finding a basement contractor experienced with polyurethane floor leveling? Toronto Basement Remodeling can match you with local professionals who specialize in concrete repair and basement foundation issues.