If your concrete is sinking, we recommend you consider concrete slab lifting and raising to fix it. Let’s look at what causes sunken slabs, options you have for concrete repair, and the benefits of each so you can make an informed decision.

What causes concrete to sink?

Concrete becomes unlevel or sinks for a couple of reasons:

Diagram of poor vs good compaction of soil beneath concrete

Weak soil beneath the slab because of poor compaction.

Diagram of hollow void creating uneven concrete

Voids beneath the surface caused by water erosion.

Why is it necessary to fix sunken concrete slabs?

Beyond the eyesore created when concrete deteriorates, it can be dangerous if you don’t repair sunken concrete:

  • Reduced integrity and strength of the surface, increasing the risk of further damage.
  • Tripping hazards and potential damage to equipment, inventory, and livestock.
Caution Alert sign in palm of person's hand

Should you repair or replace sunken concrete?

You can break up the old slab and have the concrete replaced, but that becomes very time-consuming, messy, and expensive. Settled concrete levelling is a cheaper solution than repouring. Raising concrete is also quick and simple, with minimal downtime. The concrete contractor simply drills a few injection holes and injects material to slowly raise the slab back to where it belongs.

Let’s compare the options for concrete slab lifting and raising

Mud Jacking

Also known as slab jacking, mud jacking is injecting a mortar mixture of dirt, aggregate, and cement through holes drilled in the concrete surface to raise the sunken slab. While this method is the least expensive option, it has a few drawbacks:

  • Holes you must drill into the concrete are significantly larger and harder to hide
  • Material is heavy and adds weight to the slab, risking further compression
  • Injected substance is vulnerable to further erosion and repeat problems
mudjacking equipment

Poly Slab Lifting

Filling voids under a sinking concrete slab with polyurethane foam injection is a slightly more expensive method of concrete lifting than mud jacking, but still about half the cost of replacing it. The additional benefits far outweigh the bump in cost:

  • The ⅝” holes are smaller and cleaner and we can colour match them when filled in
  • It requires less drilling because the substance is more liquid and flows easily
  • The lifting foam weighs 50 times less than mortar used in mud jacking preventing further settlement
  • Polyurethane is waterproof and does not erode preventing repeat issues
  • The foam expands and cures within 15 minutes so you can return to use quickly
  • We leave no mess around injection holes, and no heavy machinery or destruction is necessary
mudjacking vs poly slab lifting

What’s the right solution for you?

Think of where your cement slab is and its current condition. 

Areas inside warehouses and industrial buildings or other commercial spaces will probably favour a quick, easy, and clean repair method to reduce downtime and lost revenue. 

Even residential spices like basements and garage floors benefit from the lack of mess. No need to deal with how you are going to get heavy machinery close enough. Nor will you need to worry about damage to landscaping and surrounding areas.

Contact Brosco Concrete to discuss your options for concrete repair in Ontario and learn more about how concrete slab lifting and raising may work in your situation.

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