Open for business: Buildfix remains fully operational and our team are committed to ensuring your homes structural problems are repaired as safely as possible during the COVID-19 crisis.

Sinking Concrete

Why are my concrete slabs and floors sinking into the ground?

Book now for a FREE inspection

Leading Signs of Sinking Concrete

Concrete sinks deeper into the ground on which it sits for a variety of reasons. The reasons are similar whether they’re concrete slabs outdoors in your pool area, garden and driveway or concrete floors inside your house. To stop concrete from sinking deeper permanently, understanding the reason behind the sinking is of tantamount importance. If you’re wondering why you have sinking concrete outside and/or inside your home, read on for some of the top reasons.

Flooded aprtment complex

Sinking Concrete Cause No. 1:
Stormwater Damage

Flooded or overflowing stormwater drains can be one of the biggest reasons for sinking concrete. Instead of directing water away from your home, they direct water towards and around its foundations.

With nowhere for the water to run off, the water can only soak into the ground underneath your concrete floor, driveway, stairways, patios or pool area. This excessive soaking causes soil erosion leading to instability of the ground and eventually sinking.

Clogged gutters

Sinking Concrete Cause No. 2:
Poor Drainage

This is a similar cause to stormwater damage in that there’s an overflow of water. But instead of the water coming from overflowing or flooded stormwater drains, it comes from your home’s burst, cracked and/or unconnected pipes.

The malfunctioning pipes leak and pool water into specific spots underneath your concrete slabs and floors. This causes the soil to become saturated, weak and unstable leading straight to sinking concrete.

Larger excavator

Sinking Concrete Cause No. 3:
Poor Compaction of Sub-Soils

Builders have a responsibility to compact soils before constructing a home upon it. Compacting soils drives air out from between the soil grains, densifying the ground to make it more stable to build on. Sometimes, builders deliberately skip the soil compaction process to save time, only complete a fraction of the process or forget it entirely.

In any case, soil that isn’t compacted properly is still full of air. Heavy concrete placed on top of a surface like this is bound to sink.


Sinking Concrete Cause No. 4:

Concrete can sink due to intense vibrations in the ground. Excavators operating at a nearby construction site, semi-trailers passing by at high speed on a local freeway and planes taking off and landing at a nearby airport can all bring on these intense vibrations. These vibrations tend to shake and aerate soil which eventually leads to instability and sinking concrete.


Sinking Concrete Cause No. 5:
Reactive Clay

Reactive clay soil is a dense material that expands under wet conditions and contracts under dry, hot conditions. If your concrete slabs or floors are built upon reactive clay, they’re susceptible to lifting and sinking throughout the year. If your concrete happens to be sinking while the weather is extremely hot and dry, it’s likely your concrete is sitting on reactive clay soil.

Want to stop the sinking concrete now?

Sinking concrete can be a danger to you, your family and the stability of your home’s structure. If you want to stop your concrete from sinking any further, feel free to get in touch. We’re ready to help, starting with a FREE inspection.

When you work with us, we promise

  • Free structural inspections
    We take a look at your home’s cracked walls at no charge.
  • Personal, friendly service
    We’ll treat your home as if it’s ours.
  • Simple, transparent quotes
    Our quotes come with easy to understand computer-generated drawings that detail our proposed solution.
  • Minimal disruptions to your life
    Repairs to your cracked walls shouldn’t take more than a day.
  • Minimal disruptions to your home
    We don’t use underpinning and we don’t knock down walls.
  • Affordable pricing
    Unlike many other building companies, we typically only charge between $4,000 to $8,000 to repair cracked walls. See our full list of prices.
  • Permanent fixes
    We’re thorough in what we do, cracked walls we fix will stay fixed.
  • 10-year warranty
    In the rare case the wall cracks come back, we’ll be back too, at no extra cost.

Book a FREE inspection of your sinking concrete today!

Book a FREE inspection of your sinking concrete today!

Don’t just take our word for it

  • We’re the Experts in Wall Crack Repair, Foundation Stabilisation and Damp Treatment

    What you can expect

    Buildfix truck icon

    Simple, transparent quotes

    Our quotes are easy to understand and accompanied by drawings detailing our solutions. No technical jargon – we promise.

    Buildfix cog icon

    Fixed, affordable prices

    Once the price has been quoted, that’s what the job is going to cost. We don’t add extra costs at the last minute. No tricks.

    Carry out repairs for free

    Permanent repairs

    Anything we repair or enhance stays that way. Otherwise we come back to carry out repairs again for FREE.

    Ten year warranty

    10-year warranty

    You’re covered for 10 years from the day we finish our work.

help and advice

A resource collection of articles, tips and advice