Clay

We’ve done quite a few gardens around the Crewe area, where the ground conditions are potentially problematic.

Whilst it is more stable than sandy soil, the problem is that Clay expands and contracts with moisture, or a lack of it. This results in ground movement, which can destabilise the work you’ve had done - normally in the first year or two. Commonly seen in patios cracking with the heave and haul of the ground.

The basics of non-woven membrane and well compacted Type 1 MOT (50mm layers) are even more critical with clay soils as the mineral composition of clay can basically weaken the cement over time or inhibit its curing. A concrete / mortar slab of any form should never ever be in direct contact with clay!

Beyond these basics of patio installation, we always go further to safeguard the installation on clay ground, with the addition of concrete fibres into the mix. These give additional structural strength to the mix.

Where a hard clay pan has been particularly close to the subbase layer, whilst excavating as much as possible, we also use biaxial membrane or sometimes steel mesh.

Furthermore, if the natural presence of the hydrating water is capped off from the clay, the risks are higher. So, an additional measures to safeguard the installation may include flexible land drains under the subbase, designing in water-absorbing shrubs or free draining shingle.

Basically, different measures can be used to maintain the natural hydrology of the ground and add structural strength. These are the aims when landscaping on clay soils for long lasting, strong and durable patio or walling projects.