Artificial Grass Laying Course – Grit v Grano

What is a laying course?

Below the artificial grass and on top of the all-important sub-base is the laying course. This provides a smoother surface than the sub-base for the grass to sit on and also provides a better feel under-foot. 

There is ongoing debate between what aggregate to use for the laying course. It’s only 25mm deep, but it matters. 

In this article, we are going to discuss the pros and cons of grit sand and grano chippings. 

Grit Sand 

Grit sand, sharp sand, concreting sand – different name, same thing. It is a rougher, coarser sand commonly used and readily available. 

Ideal for laying block paving on or to make concrete with, it screeds and compacts fairly well to create a smooth surface, which is what you need for artificial grass to sit on.  

Some tradespeople feel that because grit sand typically has finer grains in it, that these may eventually wash away over time, particularly through a permeable sub-base if opting for a 20mm stone over MOT Type 1. If so, the grit sand may eventually become looser and over time cause potential issues with how the artificial grass looks and how it feels under-foot. 

It is also arguably more absorbent than granite chippings, which isn't ideal for dog owners who may frequent their artificial lawn.

Grano Dust 

Grano, Granite Dust or Granite Chippings is typically a 6mm to 0mm crushed granite aggregate.  

A versatile product, commonly used to form a strong concrete, it is perfect to use as a laying course beneath artificial grass. You may also find Limestone Dust more readily available dependant on location which is an equally suitable alternative. 

Most professional installers feel that because Grano is coarser, it binds together better – preventing it from moving under-foot. The larger granules are also less likely to wash away like some fear with grit sand.

Perhaps the greatest benefit of using Grano, is that it allows for better drainage versus grit. This is a fantastic benefit for pet owners, and coupled with a 20mm stone sub-base, should provide a well-functioning soakaway to prevent a waterlogged garden. 

Which to use? 

Ultimately, most professional installers, and ourselves, would recommend granite chippings. It compacts better, aids drainage and is likely to outlast grit sand.

Grano dust or Limestone fines are increasingly more available at local builders merchants who should more-often-than-not be able to supply in bulk bags. It is slightly more expensive that grit, but not massively.