Case Study: Patio Rebuild on Unstable Clay Ground

At Fusion Groundscape Solutions, we’re often called to rebuild patios that have failed over time due to poor groundwork. This project is a perfect example — an older patio on a new build property where the clay ground and weak sub-base had caused serious movement and sinking.

Project Overview

Location: New build property
Issue: Existing patio lifting, sinking, and uneven
Ground type: Heavy clay
Solution: Full excavation and rebuild using geotextile membrane, Geogrid 3, MOT Type 1, reinforced concrete with steel mesh, and Kandla Grey sandstone paving

The Problem

The existing patio had been in place for several years, but the ground beneath had become unstable. The homeowner noticed slabs starting to lift, crack, and move, with poor drainage causing puddles to form after rain.

Once we lifted the old paving, it quickly became clear why. The sub-base was a combination of stone, clay, and old screed, with no membrane or structure to separate it from the soft clay beneath. This type of foundation is unable to cope with moisture or ground movement, leading to uneven and failing paving over time.

Our Solution

Because the ground was soft and unpredictable, we designed a full stabilisation and rebuild system to give the new patio a rock-solid foundation.

1. Excavation & Ground Preparation - All failed material was removed down to stable ground. We then levelled and compacted the area, preparing it for the correct installation layers.
2. Geotextile Membrane - A heavy-duty geotextile membrane was laid to separate the clay from the sub-base, preventing contamination and maintaining long-term stability.
3. Geogrid 3 Reinforcement - On top of the membrane, Geogrid 3 was installed to lock the MOT hardcore together and distribute loads evenly — essential on soft clay soil.
4. MOT Type 1 Sub-base - Several layers of MOT Type 1 were compacted to create a strong, load-bearing foundation. The geogrid reinforcement increased stiffness and reduced the risk of settlement.
5. Reinforced Concrete Base - A layer of reinforced concrete with steel mesh was poured over the compacted sub-base to further stabilise the structure and prevent cracking or movement.
6. 40mm Laying Bed with Priming Slurry - A consistent 40mm mortar bed was laid on the cured concrete, with priming slurry applied to the underside of each slab to ensure a permanent bond.
7. Kandla Grey Sandstone Paving - Finally, we installed Kandla Grey sandstone slabs, providing a durable, elegant, and low-maintenance finish suitable for any patio or outdoor space.

The Result

The finished patio is level, solid, and built to last. By combining geotextile, geogrid, reinforced concrete, and slurry-bonded sandstone, we eliminated all previous issues — no more sinking, rocking, or water pooling.

The homeowner was delighted with the transformation: a beautiful, long-lasting patio that performs as well as it looks.

Strong Foundations. Professional Finish.

At Fusion Groundscape Solutions, every project starts with proper groundwork. We don’t just lay paving — we build lasting structures that stay stable and attractive for years.

Contact us today for expert advice or a free quotation on your next driveway or patio project. We’ll make sure it’s built properly - from the ground up.