concrete slab that has settled and shifted

Concrete slabs are often used as a foundation for a garage, patio, pool deck, steps, walks, or driveway. They also often serve as an inexpensive alternative to building a full basement or even a crawl space.

Occasionally a slab can sink due to a variety of reasons, usually due to settling. A process known as “slab jacking” or “mudjacking” is used to level a concrete slab or foundation.

The cost of leveling a slab usually averages around $500 to $1500, but it all depends on the size of the area to level, the materials used, and the labor involved. Foam leveling will likely cost around $2000-2500 for a 100 square foot slab.

Why Level When You Could Replace?

What you must ask yourself here is, does it make more sense to spend twice as much or more to demolish the old slab, haul it away, reform, and repour the concrete?

A new slab might be a good option, but consider the cost of repair will likely be significantly less. The price of hauling away the old slab could cost as much leveling it. Concrete leveling is less expensive, more convenient, and could give you a finished product in less than half time that is almost as good.

Granted, you might need to fill the cracks, sand, and polish the leveled slab, but you would have to do some finishing for a new slab anyway. Many homeowners are even getting creative with concrete slabs by using epoxy and other finishing products to make their slab look impressive without going to the expense of floor covering.

Leveling Options

Depending on your budget and what the leveled slab will get used for, leveling is an equally good option and cheaper than new.

Self-Leveling

This option gets used primarily for small sections of slab that have cracks or a small amount of sagging. This option is the cheapest method of leveling a concrete slab. New concrete gets poured over the surface, it will fill in the areas of depression and cracking and when finished, looks the same as a new slab.

However, this process will not affect the footing around load-bearing walls, so if those are sagging, the settlement will continue unless the walls are lifted and reinforced.

Self-leveling uses a polymer compound that costs about $1.25 per square foot, on average. Depending on how much work is involved, the contractor will usually charge a flat rate for labor; typically two or three times what the materials cost.

Therefore, a 10’ x 10’ slab or 100 per square foot slab will cost $125 for materials and $375 for labor, or a total of $500.

Mudjacking

Mudjacking uses a process of drilling one or two-inch holes into the concrete and injecting concrete mix underneath to lift the slab and level it. It can be used to raise any size slab and will even lift load-bearing walls somewhat. However, the effect may only be temporary, depending on the soil.

The settlement will continue if the soil underneath is not strong and weather conditions during freezing and thawing will cause heaving and expedite settlement. Foam jacking is the preferred method when load-bearing walls need leveling.

Mudjacking will use a compound of concrete mix and pond sand to fill the holes drilled. This process generally costs $5.00 per square foot for materials and add anywhere from two-thirds to the same price as materials; so $365 up to $500 for labor.

Therefore, a 10’ x 10’ slab or 100 per square foot slab will cost $500 for materials and $365 or $500 for labor – for a total between $865 to $1000.

Foam Jacking

Foam can also be used to fill holes and cracks, and push up areas under the slab that mud is too thick to fill. Foam can even lift load-bearing walls and is strong enough to resist sagging. Although it is much more expensive than mud jacking, it last longer and fills better than mud. In most cases, it is the preferred method.

In this process, lightweight foam is injected through 5/8″ holes in the slab. The polyurethane foam can get injected with more pressure. Therefore, when it expands, it lifts the slab before it hardens.

Foam costs about $20.00 per square foot, on average. Depending on how much work is involved, the contractor will usually charge a flat rate for labor. Labor costs are usually about the same as mud jacking; $365 to $400 for a one or two-hour project.

Therefore, a 10’ x 10’ slab or 100 per square foot will cost $2000 for materials and $365-400 for labor, for a total of $2000-2500.

Leveling Cost Factors

These figures are the average price across America and will vary depending on your location and the amount of work done. The cost in your area could be much less or more depending on the price of labor and materials.

A contractor who charges more than the average rate might use better quality products, pay more to laborers, or they are busy due to quality craftsmanship and personal references.

When you get a price quote or estimate, you must consider everything the contractor will provide. Even when self-leveling a concrete slab, the process used to finish the concrete can affect the price.

Consider whether it will just get leveled, leveled and brushed, or if the contractor guarantees a smooth surface. Contractors often add $4-10 per square foot to finish concrete, depending on the process.

We recommend getting at least three estimates from contractors experienced with this type of work.

Are you thinking of installing a new slab? Try our concrete calculator to get a better idea of how much materials for a new slab will cost.