Slab Lifting vs Replacement: Mudjacking and Polyjacking Explained

Published: April 29, 2026

A driveway slab that has dropped two inches at the seam is more than just an ugly eyesore. It is a dangerous trip hazard, a major drainage problem, and a flashing warning sign that something underneath the surface is wrong.

Homeowners across the GTA usually assume the only fix is to tear it out and pour a brand new one. However, in 2026, that is rarely the cheapest or the best initial option. Slab lifting (through mudjacking or polyurethane foam) can level a sound slab in a single afternoon for a fraction of the cost of a full replacement. The trick is knowing when lifting works and when it does not.

SVD Restoration handles both advanced lifting techniques and full replacements, including comprehensive concrete and foundation repair solutions, so we give you the unbiased truth based on your property’s needs. Here is how to choose the right path.

What Sunken Concrete Actually Means for Your Property

Concrete itself does not sink. It is too heavy, too rigid, and too dimensionally stable for that. What actually sinks is the soil underneath it. According to engineering principles backed by the Cement Association of Canada, concrete relies entirely on its sub-base for structural load-bearing capacity. When the support material under a slab erodes, compresses, or washes out, the heavy slab naturally follows it down.

This distinction matters because the most common homeowner assumption: the slab is broken, so we need a new one, is usually wrong. If the slab is structurally sound (meaning no deep through-cracks, no exposed rebar, and no major surface scaling), lifting it back into place is faster, cheaper, and just as durable as a replacement.

The most common causes of soil settlement under GTA slabs include:

• Poor original compaction: Backfill dirt that was never properly compacted by the original builder will naturally settle for 5 to 10 years.
• Water erosion: A downspout discharging right next to the driveway actively undermines the soil over time.
• Tree root decay: Roots grow under the slab, force it up, and then die back, leaving massive empty voids behind.
• Frost heave: Repeatedly pushing soil up in the winter and letting it settle differently in the spring thaw.
• Plumbing leaks: A slow leak from a buried supply line can wash out cubic feet of soil, which often leads to water pooling against the house and requiring professional foundation crack repair if it reaches your basement walls.

What is Mudjacking? The Traditional Slab Lifting Method

Mudjacking is the original slab-lifting method that contractors have used for decades. The team drills a series of small holes (about 1.5 inches across) directly through the sunken slab. They then pump a thick slurry mixture of cement, soil, sand, and water under high pressure into the void below. The slurry fills the empty space, compacts the surrounding soil, and hydraulically lifts the slab back to its original grade. The drill holes are then patched with a color-matched concrete grout.

What is good about mudjacking:

• It is highly cost-effective and typically falls on the lower end of standard repair pricing.
• The fill material is natural and highly compatible with the existing soil profile.
• It is a reliable, proven technique used for over 60 years.

What is not so good:

• The wet slurry adds massive weight to the soil column (about 100 lbs per cubic foot). On weak soils, this added weight can actually cause future re-settlement.
• The drilled holes are fairly large and remain visible after patching.
• You must wait at least 24 hours for the slurry to cure before you can drive on it.
• If rainwater finds the slurry before it fully cures, it can easily wash out.

Understanding Polyjacking: The Modern Polyurethane Foam Solution

Polyjacking (often called polyurethane foam injection) is the modern, high-tech alternative. The contractor drills much smaller holes (about 5/8 of an inch) through the slab and injects a specialized two-part polyurethane resin. This resin chemically reacts with itself and violently expands to about 25 times its liquid volume, instantly filling voids and lifting the slab in a matter of minutes.

Why we use polyjacking on most residential jobs in 2026:

• The cured foam is incredibly lightweight (about 4 pounds per cubic foot). It lifts the slab without adding heavy loads to already weak soil.
• The cure time is basically instant. Customers can safely drive their cars on the slab within 15 to 30 minutes.
• The tiny drill holes are nearly invisible once they are patched with grout.
• The foam is entirely hydrophobic, meaning it repels water and cannot be washed away by future rain or drainage issues.
• It remains dimensionally stable in the earth for 50+ years.

The catch: The premium chemical materials make polyjacking slightly more expensive than traditional mudjacking.

When Complete Concrete Replacement is Your Only Option

Lifting only makes financial sense if the slab itself is in great shape. If the physical concrete has failed, no amount of foam or mud underneath it will save it. You must replace the slab entirely if any of these conditions are true:

• There are more than three significant structural cracks (wider than 1/8 inch) spiderwebbing across the slab.
• You have deep through-cracks that span the full thickness of the concrete.
• Severe surface scaling has peeled away the top layer and reached the rough aggregate stone beneath.
• You can see rusting, exposed rebar, or wire mesh anywhere on the surface.
• The original slab was poured too thin (less than 4 inches thick), which was common in 1960s GTA driveways.

In these cases, you will need to schedule a complete professional concrete removal to haul away the debris safely before starting fresh. A full replacement gives you the perfect opportunity to fix underlying drainage disasters, compact a proper gravel base, and upgrade to a beautiful decorative finish.

Cost Comparison for GTA Homeowners in 2026

Because every property is unique, giving exact numbers without an inspection is difficult, but here is how these projects generally break down based on current GTA pricing parameters:

• Concrete Repair & Lifting (Mudjacking/Polyjacking): General leveling and crack repairs typically range from $3 to $10+ per square foot, depending on the volume of material needed to fill the void. (Most contractors have a minimum site visit charge of $600 to $800).
• Full Concrete Replacement: To tear out the old slab and pour a new one, you have to account for both services. Concrete removal safely ranges from $2 to $6 per square foot, while pouring new concrete costs $8 to $30 per square foot, depending on the finish (broom vs. stamped). This puts total replacement costs roughly between $10 and $36+ per square foot.
• The Bottom Line: For a typical 200-square-foot sunken garage apron, lifting it back into place will generally cost between $600 and $2,000. Tearing it out and pouring a new one will run anywhere from $2,000 to $7,200+. The math heavily favors lifting, as long as the slab is sound.

How to Choose the Right Solution for Your Concrete

Here is the exact decision tree our estimators use in the field:

1. Is the slab structurally sound? If no, replace it.
2. Is the underlying drainage problem fixable? If you cannot stop the water from washing the dirt away, lifting it is a waste of money. Replace it and re-engineer the yard’s grading.
3. Are you okay with small drill-hole patches? If you want absolute visual perfection, you must lean toward replacement.
4. Is the slab relatively young and your budget tight? Lift it.
5. Do you need the driveway back in service the exact same day? Polyjack it.
6. Do you need 50+ years of additional life? Polyjack it or invest in a brand new concrete pouring project.

The single biggest mistake we see homeowners make is lifting a slab without fixing why it sank in the first place. If a broken downspout is still actively washing soil out from under the driveway, the slab will sink again in two years. Always fix the drainage first, then lift the slab second.

Frequently Asked Questions About Slab Lifting

Is polyjacking really better than mudjacking?

For most residential jobs in the GTA, yes. It cures faster, it is significantly lighter on weak soils, it is immune to water washout, and the drill holes are much smaller. Mudjacking still has a role on massive commercial warehouse floors where bulk material cost matters more than aesthetics.

How long does a lifted slab actually last?

The polyurethane foam itself is dimensionally stable in the earth for 50+ years. The slab, however, will only last as long as the concrete was originally going to last. If you lift a 25-year-old slab, you are simply getting back the good years it had left.

Can any concrete slab be lifted?

No. Slabs with major structural cracks, severe surface scaling, or exposed rebar have lost their structural integrity and will simply break apart under the pressure of the lift. They must be replaced.

Will my driveway look fixed after polyjacking?

It will be perfectly level again, eliminating the trip hazard. The drill holes (which are about the size of a dime) are patched with a carefully color-matched grout, making them barely visible from a few feet away.

How quickly can I drive on a polyjacked slab?

You can safely drive your vehicle on it 15 to 30 minutes after the injection is complete. Foot traffic is fine immediately.