What does a sinking floor mean?

Sinking concrete floors are an indication of building subsidence (when the ground sinks due to movement of underground material).

A building can sink at various points or the collapse can be spread across the entire footprint of the foundation, depending on where the affected ground is and how large an area it is. This can be very serious, and if left untended is likely to worsen, creating further building subsidence and other consequent damage.

Sinking structures in mining and resources

Sinking structures, floors and ground create many problems in the Mining and Resources sector. If not resolved promptly, and correctly, mine subsidence issues can cause costly downtime and even become hazardous.

For many years Mainmark’s methods have been used in raising foundation, re-levelling and re-supporting on-ground and in-ground mine-site structures, including:

  • Coal loader towers
  • Conveyer belt pedestal bases
  • Rock-breaker footings
  • Rail index machine slabs
  • Vehicle service centres & garages
  • Stacker reclaimer rails
  • Office buildings
  • Conveyer belt counter-weight towers
  • Railway lines
  • Engineering workshops
  • Parking areas
  • Loading docks

Mainmark methods are used successfully on any building, of any size.

What causes subsidence?

There are many different causes of subsidence and various contributing factors. All involve some sort of change in the ground, which, in turn, generates movement of the soil. For example, droughts dry the ground, resulting in the soil (especially clay) contracting. Seismic activity shakes the ground, often resulting in liquefaction which ‘squeezes’ liquid up from the ground. Excavation and construction, even heavy traffic and machinery vibration, can move, displace and alter the condition of the ground.

As well, different types of ground are more affected by different conditions. For example; clay is particularly prone to contracting in drought conditions, gravel and stony grounds can be more affected by nearby excavation, and excess water has a softening effect on dirt. Subsidence can happen over large areas of land or in a small targeted area. It can occur over a lengthy period of time, or can be an immediate reaction to nearby activity or natural events. When ground has been affected, building subsidence is common. Foundations or footings are no longer ably supported, sinking due to weak ground.

Likely causes:

Water flooding the ground

Drought drying out soil

Washaways from broken pipes (such as water, sewer, stormwater drainage)

Poorly compacted fill

Liquid, gas or mineral resources being removed from the ground


Earthquake and seismic activity

Tree roots can suck moisture from the ground

Vibrations caused by heavy road traffic or by machinery

Absence of an organised footing system – in very old buildings or in buildings with additions or alterations

Nearby excavation

Heavy loading

Deterioration of retaining walls

How to fix sinking floors?

The only way to fix sinking concrete floors is to raise foundation, re-level and re-support the building. Mainmark specialises in concrete levelling. Level correction not only re-levels a building, but also strengthens any weak ground under and around the perimeter of the foundations, ensuring a stable base and helping to avoid any recurring sinking issues. Traditional level correction or “underpinning” methods involve excavating or digging up parts of the foundation, pouring in concrete, waiting for it to set and then jacking up the building off the concrete blocks. This method can be:

  • time consuming (often requiring weeks or months)
  • messy
  • usually means you’ll have to vacate part or all of the building while tradespeople work

Mainmark methods are much friendlier, both to the building and to those that occupy it. Our non-invasive concrete re-levelling techniques are cost and time efficient.

Various product warranties and Building Code requirements apply (please contact us to see which apply in your region or country).

Key benefits of Mainmark’s level correction methods include:

There is minimum disruption to the site, no excavation and no mess

Projects are completed in a time-frame significantly less than traditional methods

Non-invasive techniques mean further damage to the site, and the landscaping around it, is absolutely minimal. We don’t tear up areas or excavate ground, creating costly and time-wasting messes

Trip hazards are eliminated. Vehicles and machinery can run smoothly almost immediately

Re-levelling is completed in a fraction of the time of traditional methods. There’s no cutting out of old slabs and no waiting days for new slabs to cure

There are usually substantial cost savings, in comparison to traditional methods

Weight is no problem, in fact the greater the weight on the ground the more it can be compacted. Huge ground support can be created, especially when the area is loaded with weight

There’s minimal interruption to the site, operations can often continue while the work is being completed

The methods we use strengthen weak ground, so the site becomes level and more stable.

Mainmark level correction methods used in the mining and resources sector: