How to Fix Sinking Concrete Floors

Have your concrete floors started to sink? It can happen gradually or very quickly.

It can be very difficult to notice and measure a gradually sinking foundation when you are walking or working on it daily. In most case, the sinking will only be noticeable once major damage has been done. Major damage is much more expensive to fix so keep an eye on your floor and monitor it for any changes to save your wallet.

When you notice your floors have sunk it is important to identify whether the damage is structural eg. support beams or posts, or whether the problem stems from issues even deeper down. Fixing the only the structural issues and not any subsidence issues means you have only dealt with the superficial issue and this will cause more issues down the track.

What is the cause of sinking floors?

Sinking concrete floors usually indicate building subsidence.

Building Subsidence: the process by which an area of land sinks to a lower level than normal, or by which a building sinks into the ground.


The different ways floors and buildings sink include:

  • Across the entire foundation
  • At specific points across the foundationThe way in which a building sinks will depend on the location of the affected ground and the size of the area

What are the Causes Of Building Subsidence?

Changes in the ground can result in the movement of underground material, which is usually soil when it comes to buildings.

Subsidence occurs when a change in the ground results in movement of underground material (with buildings, this material is most likely to be the soil).

Specific causes of subsidence include:

Drought: soil can contract without sufficient water
Flooding: with too much water the ground can be flooded
Liquefaction: liquid can be seized from the ground by earthquakes or similar activity that shakes the ground
Vibration can be caused by heavy traffic or machinery used
Excavation work or construction sites in a nearby area

Do You Need to Fix a Sinking Floor?

Yes, sinking floors should be dealt with quickly. If you don’t fix the sinking floors they will continue to worsen and foundation problems can lead to structural issues with the building.

So how do you fix a sinking concrete floor? The floor needs to be raised and re-levelled to support the building. This will strengthen weak ground to create a stable base and avoid further sinking issues in the future.

Chemical underpinning is often a very effective method.

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