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 floors in commercial and industrial structures

Mainmark methods can lift buildings of any size, having been used with great success on thousands of projects around the world. The level correction solutions we provide to the commercial and industrial sectors are sought for many reasons; a significant factor being how cost effective and time efficient the processes are.

Sinking floors can cause many problems in the Commercial and Industrial sectors, often with negative impact on equipment and machinery. Bringing the building and its floors back to level means everything is back on an even keel, optimising business output. Most importantly, structural damage is resolved, and the future of the building is sound. In fact, our methods actually improve the building’s bearing capacity. Mainmark methods are suitable for any building, of any size. We also re-level parking areas, loading docks, hardstand areas and driveway.

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

There is little, if any, downtime to the business. In many cases, the site can still operate, with staff able to continue working (this is case-dependent, damage may be such that this is not possible)

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

Non-invasive techniques keep further damage to the building, and the landscaping around it, to an absolute minimum. We don’t tear up floors and excavate ground, so do not create mess

Internal and external wall cracks generally close up, leaving only cosmetic treatment (plastering, painting and re-pointing brickwork)

Jammed doors and windows can usually operate properly again

Trip hazards are eliminated. Often, forklifts and trucks can run smoothly just 30 minutes after the floor is re-levelled

There’s usually no need to move stock or machinery off the floor. No excavation. No mess

Warehouse shelves and conveyor systems usually return to their correct positions as floors are re-levelled

Most large factory and warehouse floor repairs are completed in a day or two. There’s no cutting out of old slabs and no waiting days for new slabs to cure

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

Mainmark level correction methods used on commercial and industrial buildings: