According to recommendations, you should lay a layer of sharp sand to a thickness of 10 to 15mm under artificial grass.
Recommended Sand Thickness
Based on the provided reference, the suggested thickness for the sand layer beneath artificial grass is between 10mm and 15mm. This layer is relatively thin compared to the sub-base beneath it.
Purpose of the Sand Layer
The primary function of this sand layer is to "blind" or smooth out the top surface of the sub-base (like crushed aggregate) before the artificial grass is installed. This creates a level, firm surface for the grass to sit on. It helps to:
- Fill small gaps and imperfections on the sub-base surface.
- Provide a smooth, even finish.
- Ensure a firm base, as stated in the reference ("it should be firm").
What Type of Sand?
The reference specifically recommends using sharp sand. This type of sand is gritty and coarse, making it ideal for creating a compact and stable base layer. It allows for good drainage, which is crucial for preventing waterlogging under the artificial turf.
Typical Base Construction
A typical base for artificial grass involves several layers to ensure stability, drainage, and a smooth finish. The sand layer is just one part of this system:
- Excavation: Removing the existing turf and soil.
- Sub-base: A layer of compacted aggregate (like crushed stone or MOT Type 1), typically 50-75mm thick, provides the main structural support and drainage.
- Geotextile Membrane (Optional but Recommended): Placed over the sub-base and under the sand to help prevent weed growth.
- Sand Layer: The 10-15mm layer of sharp sand for blinding and leveling.
- Artificial Grass: Rolled out and secured on top of the sand layer.
Here's a simplified look at the layers:
| Layer | Material | Typical Thickness | Purpose |
|---|---|---|---|
| Sub-base | Crushed Aggregate | 50-75mm | Drainage, structural support |
| Weed Membrane (Optional) | Geotextile | N/A | Prevents weeds |
| Sand Layer | Sharp Sand | 10-15mm | Blinding, leveling, firmness |
| Top Surface | Artificial Grass | Varies | The visible grass surface |
Using the correct amount and type of sand is key to achieving a professional-looking and durable artificial lawn installation. The 10-15mm thickness provides the necessary blinding without adding excessive depth or instability.
