Sinking & Settling Concrete Slab Foundation Repair in the Province of Quebec

diagram of a repaired concrete slab floor

Concrete slab piers can extend deep below the floor to reach competent supporting soils and permanently stabilize the floor.

Do you have a concrete slab floor that is showing signs of sinking, sagging, or settling? Are the walls separating from the floor below or ceiling above?

IF you have a problem like this in your home, you could have a sinking or settling concrete floor slab. This problem can lead to cracks in floors and walls, uneven surfaces, and a weakened foundation.

Luckily, the foundation repair experts at Systèmes Sous-sol Québec can help you solve this problem permanently! We provide a complete foundation repair solutions in Quebec City, Montreal, Laval and nearby areas in Quebec. Call us today to get a free estimate.

Signs Of Slab Settlement

When a floor slab settles, the damage can manifest itself in many ways. Along with cracks in the concrete, the floors can separate from the walls as they sink downwards. Alternatively, the interior wall may be pulled down with the floor, instead separating from the ceiling. Walls can also pull away from other walls, and interior wall cracks can form -- commonly off the corners of interior doors.

(Click each photo to enlarge.)

Slab floor cracks showing in a Saint-odilon home Large slab floor cracks in a Lourdes home A floor slab separating from the wall in a Joly home. A partition wall separating from the floor in a Sherrington home.
a sinking floor leaving a large gap between the wall and floor in a Sainte-clotilde-de-chateauguay home The ceiling and wall separating as the wall sinks with the slab floor in a Saint-michel home partition walls being pulled away from the foundation walls in a Saint-isidore-de-laprairie home. wall cracks along a doorway in a Saint-eduoard-de-napierville home.

What Causes A Concrete Floor Slab To Settle?

When a concrete floor settles, it can mean serious damage to your home. The causes of floor slab settlement are almost always due to the soils underneath being unable to support the weight of the concrete. They often accompany other foundation problems in your home.

The three most common causes of settling concrete floor slabs are as follows:

(Click for more information.)

Dry, cracking clay soils

Drying/Shrinking Of Soils Under The Slab

soil erosion

Washout Of Soil Underneath The Slab

A backhoe excavating a foundation

Poor Compaction Of Foundation Fill Soils

Installing The Foundation Supportworks Slab Pier System

We use foundation piers to stabilize the concrete floor slab in your home. This method provides the best opportunity to relevel the floor and lift non-load bearing partition walls that may have settled along with the slab. To install our system, our contractor will take these six steps:

Coring the concrete of a concrete slab floor in Kahnawake

Preparing for Installation

Before the installation day, a representative from our company will have already inspected your foundation issue. At that time, a foundation repair proposal was put in writing.

Your foundation repair experts will use that proposal to map out the locations where the slab piers will be installed. At the beginning of each slab pier installation, a small hole is cored through your concrete slab floor. This hole will create an access point for the slab piers that are about to be installed.


A three piece foundation slab bracket assembled underneath a concrete slab floor.

Position Slab Bracket

To give the slab pier something to "lift," a slab bracket is positioned beneath the concrete slab.

The Foundation Supportworks Slab Pier System uses a three-piece slab bracket that is assembled underneath your concrete floor, allowing for a much smaller hole to be cored in your concrete slab. Additionally, this larger bracket reaches across more area along your floor, creating a more even distribution of weight.


Driving foundation piers into the floor in Brossard.

Install Steel Tubes

Steel tubes are hydraulically driven down through the bracket to the competent soils beneath.

These steel tubes are the real strength of the foundation pier system -- and are responsible for transferring the home weight to strong supporting soils. To prevent corrosion, Systèmes Sous-sol Québec has slab piers available that are designed using galvanized steel. This ensures the quality and long-lasting strength of your slab pier system.


Using steel slab piers to transfer the weight of the concrete slab to the soil beneath in Repentigny.

Transfer Slab Weight To Soil

The weight of the concrete slab is transferred through the piers to the load-bearing strata underneath your home.

As the system lifts your concrete slab floor upwards, the sinking movement of your floor will be permanently halted. Often, it will also be possible to lift the concrete slab back to a level position.


A foundation slab pier after installation and grout injection has been completed in a Saint-Jean-sur-Richelieu home.

Inject Grout Fill

Once the concrete slab has been lifted, a void will be present underneath the removed floor.

Additionally, if your floor had been sinking because of compacted soil or washout, a gap existed even before the installation. To address this, we carefully pump grout under the slab to fill in all empty spaces.


Repairing the cored holes in the concrete slab floor with fresh concrete and cleaning up the Terre-bonne home.

The Cleanup

At Systèmes Sous-sol Québec, we take pride in leaving your home looking clean and neat. Once the installation is completed, we repair all cored holes with concrete, making your final installation virtually invisible.

Any debris generated during the installation is cleaned up and removed by us. And once we're done, you can rest easy, knowing that you have a 25-year warranty on manufacturer's defects, as well as a performance warranty from us.

Looking For Foundation Slab Repair Contractors In QC?

At Systèmes Sous-sol Québec, we provide proven solutions for concrete slab floor leveling -- as well as other foundation repair solutions -- to homeowners throughout Quebec. We provide each of our customers with a free, no obligation slab repair quote, in writing, before any work is done. To schedule your appointment, call or e-mail us today!

We proudly offer all our foundation repair services in Laval, Quebec City, Montreal, Levis, Sherbrooke, Gatineau, Longueuil, Trois-Rivieres, Saint-Jean-sur-Richelieu, Terre-bonne and throughout the surrounding areas.

Drying & Shrinking of the Soil Under the Slab

HVAC (Heating, Venting, and Air Conditioning) systems may be installed beneath the floor slab. Over time, the ductwork can leak air, which can dry out the soil.

As the soil dries and shrinks, gaps form under the floor slab, creating voids. Because the soil no longer supports the floor slab, the floor begins to crack and sink into the voids.

street creep symptoms in a driveway in Ste-marguerite-de-dorchester

Washout of Soil Under the Slab

This is usually caused by plumbing leaks. If the plumbing leak is severe and there is a path for the water to flow through, it can wash soil out from under the slab.

With a void underneath the floor, there's nothing supporting the concrete slab anymore. In time, it begins to crack and sink downwards.

garage walls cracking due to street creep

Poor Compaction of Fill Soil

During construction of a new home, layers of soil are commonly moved around or spread out to get to the desired grade level. When the home is built, footings may be deepened to extend below weak fill soils and avoid a foundation settlement issue.

The slab, however, remains on the fill soils. If the fill was poorly compacted, the fill soil compresses and settles, and a void is formed under the slab. In time, the slab cracks, breaks, and settles into the void.

foundation wall cracks due to street creep in Ste-marguerite-de-dorchester

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our service area

We serve the following areas

Ontario
  • Cornwall
  • South Glengarry
  • South Stormont
Quebec
  • Athelstan
  • Baie-d'urfe
  • Beauharnois
  • Cazaville
  • Coteau-du-lac
  • Dalhousie
  • Dewittville
  • Elgin
  • Franklin
  • Gatineau
  • Godmanchester
  • Havelock
  • Hinchinbrooke
  • Howick
  • Hudson
  • Hudson Heights
  • Huntingdon
  • Les Cedres
  • Les Coteaux
  • Melocheville
  • Notre-dame-de-l'ile-perrot
  • Noyan
  • Ormstown
  • Pointe-des-cascades
  • Rigaud
  • Riviere-beaudette
  • Saint-anicet
  • Saint-antoine-abbe
  • Saint-chrysostome
  • Saint-clet
  • Saint-etienne-de-beauharnois
  • Saint-louis-de-gonzague
  • Saint-paul-de-l'ile-aux-noix
  • Saint-polycarpe
  • Saint-stanislas-de-kostka
  • Saint-telesphore
  • Saint-urbain-premier
  • Saint-valentin
  • Saint-zotique
  • Sainte-agnes-de-dundee
  • Sainte-barbe
  • Sainte-justine-de-newton
  • Sainte-marthe
  • Sainte-martine
  • Salaberry-de-valleyfield
  • Tres-saint-redempteur
  • Vaudreuil-dorion
Our Locations:

Systèmes Sous-sol Québec
1620 boul Saint-Elzéar O
Laval, QC H7L 3N2
1-514-800-6406