Sunken Floors

Sunken Floor Repair & Subsidence Specialists Across New Zealand

If your home has sunken floors, uneven flooring, cracks in walls, sticking doors or windows, or gaps around frames, it is likely experiencing foundation movement or subsidence.

In New Zealand, sunken floors are commonly caused by subsidence, reactive clay soils, moisture changes, poor drainage, seismic activity, or weakened supporting ground beneath the home.

Mainmark is New Zealand’s leading specialist in sunken floor repair and subsidence repair, delivering fast, cost-effective, non-invasive solutions that stabilise the ground and lift and re-level sinking foundations, without excavation, demolition, or major disruption.

Why Homeowners Choose Mainmark’s Sunken Floor Re-levelling Solutions

✔ Fast installation: often completed in a single day

✔ Cost-effective: compared to traditional underpinning

✔ Non-invasive no digging, no mess, no demolition

✔ Precise lifting using engineered resin technology

✔ Proven results across thousands of projects

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Video

Residential Sunken Floors & Slabs

Our Teretek® Resin Injection technology can raise, re-level and re-support sunken floors and slabs.

Watch how our non-invasive, cost-effective technology raises and re-levels a sinking residential internal floor and external concrete slab.

Sunken Floors & Sunken Slabs

Before & After Treatment

Houses that need to be re-levelled often experience internal and external sinking floors and slabs.

These houses require their foundations to be re-levelled.

Mainmark’s non-invasive and cost-effective solutions can raise, re-level and re-support your home. Our innovative methods minimise site disruption and are completed within one day.

Before

After

Before

After

What Causes Sunken Floors?

There are many different causes of subsidence and various contributing factors.

All involve some change in the ground, which, in turn, generates movement of the soil.

As well, different types of ground are more affected by different conditions.

When ground has been affected, building subsidence is common. Foundations or footings are no longer fully supported, sinking due to weak ground.

Soil Types

Moisture levels in the soil affect reactive clays as they expand and contract.

Oversaturated clays lose their strength resulting in footing subsidence. In loosely packed soils, such as sand and silt, the fine particales in the soil can wash away causing the footing to settle.

Tree Roots

Neighbouring trees and shrubs absorb water using their roots causing movement in the soil as it soaks up moisture in the ground.

Footing Systems

Poor foundation design or inadequate compaction of soil during construction results in movement of the structure as it settles.

Excess Water

Burst or cracked water pipes including blocked sewage and rain gutters can oversaturate clay soils or wash fine particles from sand and silt soils and cause footings to subside.

Extreme or Seasonal Weather

Natural disasters such as flooding, drought and earthquakes affect soil moisture levels in particular clay resulting in excessive foundation movement.

Renovation or Construction

Vibration caused by nearby construction activity such as drilling or piling, or heavy road traffic causes soil particles to shift and settle, resulting in ground subsidence.

Sunken Floors Repairs

Why Homeowners Choose Mainmark’s Sunken Floor Repair

Fast

Our technologies have fast curing times and treated areas can be used immediately or without the delays compared to traditional repair methods.

Environmentally Inert

Our technologies use an inert material that is non-toxic and does not leach into the environment or affect the treated area.

Non-Invasive

Our solutions are of surgical nature compared to traditional methods.

Cost-Effective

Compared to traditional methods, our solutions are more cost-effective, with minimal disruption to the area.

How We Fix Sunken Floors

Step 1

Our technicians drill small holes around the problem area.

Step 2

Teretek® resin is injected.

Step 3

Unique two-in-one solution improves ground bearing capacity and fills voids

Step 4

Building is brought back to level.

Why Choose Mainmark

The Leaders in Sunken Foundation Repair

The Pioneers of Resin Injection Underpinning

The Pioneers of Resin Injection Technology in New Zealand.

In-House Engineers

Brings extensive knowledge and experience to every project.

ISO Accredited

Guaranteeing risk mitigation and operational excellence.

50 Year Product Warranty

Backed by a 50-year warranty and ongoing support you can trust.

Contact Us – Mainmark

Book a Sunken Floor Assessment in New Zealand:

If your home is showing signs of foundation movement, subsidence, or sinking foundations, acting early can prevent further damage and reduce repair costs.

Mainmark delivers fast, cost-effective, non-invasive sunken floor repair solutions across New Zealand.

Request your foundation assessment today to stop further structural damage and protect your home’s future.

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Sunken Floors FAQs

What causes sunken floors in New Zealand homes?

Sunken floors are most commonly caused by subsidence or foundation movement, where the ground beneath the home loses strength and settles. In New Zealand, this is often due to reactive clay soils, moisture changes, poor drainage, seismic activity, or weakened supporting ground.

Are sunken floors a serious problem?

Yes. Sunken floors usually indicate foundation movement, which is a structural issue. If left untreated, movement can worsen and lead to wall cracks, uneven floors, and further damage.

How do you fix sunken floors?

Sunken floors are fixed by stabilising and strengthening the ground beneath the foundation and lifting the structure back toward level.

Mainmark uses engineered resin injection to fill voids, compact weak soil, and re-support foundations.

Can sunken floors be fixed without underpinning?

Yes. Most sunken floors can be repaired without traditional underpinning using resin injection. This non-invasive method avoids excavation and concrete footings.

How long does sunken floor repair take?

Most residential sunken floor repairs are completed within one day.

Will fixing the foundation stop floors from sinking again?

Yes. By re-supporting the ground beneath your home, Mainmark treats the root cause of movement, helping prevent future sinking.

Is resin injection safe for homes?

Yes. Teretek® resin is environmentally inert, non-toxic, and designed specifically for residential foundation stabilisation.

How much does sunken floor repair cost in NZ?

Costs depend on severity and ground conditions, but resin injection is typically significantly cheaper than underpinning.

What are early signs of sunken floors?

Early signs include uneven flooring, sloping surfaces, cracks in walls, sticking doors or windows, and gaps around frames.

Who specialises in sunken floor repair in NZ?

Mainmark is New Zealand’s leading specialist in sunken floor repair and subsidence repair, with decades of experience and thousands of successful projects nationwide.

Need Sunken Floor Repair?

Book a professional foundation assessment with Mainmark NZ and find out what’s causing your sunken floors, and how we can fix them fast.

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