Paving the way with great materials

Choosing the correct foundation material for your landscaping job

I’m often asked by our customers which material is best for use as a foundation, and how to place and prepare that material in readiness for paving or concrete surfaces. In this blog I will address the first question: which material is best to use as a foundation.

My next blog will look at the process for placing and preparing your job using the material you have chosen. 

A choice of great materials

The choice of which material comes down to the type of work being done and, to a lesser extent, personal preference. Watson Davies Landscape Supplies (WDLS) stocks pit sand, quarry dust and three different grades of GAP aggregate that are suitable for use as foundation materials.

Let’s take a closer look at each of these materials: 

Pit sand

Pit sand is a largely unrefined material mined straight out of the river banks. It is widely used in the construction industry for foundation work, is more affordable than quarry dust, easy to handle and compacts nicely. It can have variable amounts of sand in it, including some stones, which can be a problem when it comes to creating a smooth finish on which to lay your pavers.  

Quarry dust

Quarry dust is produced from crushing and screening blue rock in local quarries. It is not as widely used as other materials, probably because of the additional cost involved, but it is more uniform in size and therefore easier to use. It also compacts extremely well. The absence of stones and its compaction properties make quarry dust my personal preference for paving work. 


Much like quarry dust, GAPs are produced from crushing and screening blue rock in local quarries. At Watson Davies Landscape Supplies, we stock three different sizes of GAP aggregates. GAP 20 includes all sizes of aggregate up to 20mm and, with its relatively finer size, it is suitable for use on “top” as a finishing course. The same stone size rule applies to GAP 40 and GAP 65.  Their courser size and smaller cost makes them more suitable as a base course where you have deep foundations to fill, particularly where heavy traffic is involved.

Which material is right for the job?

When it comes to paving the choice of whether to use pit sand or quarry dust is where budget and personal preference will influence your choice. Pit sand and quarry dust are ideal for work requiring an accurate finish, e.g. pavers, whereas GAPs are more suited to work where the smoothness of the foundation’s finished surface is less critical, e.g. concrete driveways and footpaths.

Laying the foundations

Once you have chosen the material that best suits your project you will need to place and prepare the material in readiness for your finished surface, i.e. pavers or concrete. Check out our step by step process for preparing a foundation for laying pavers.

If you are still unsure about which products is right for you job, please visit Dave or I at Watson Davies Landscape Supplies, they will gladly help you with your selection.

Wishing you happy and creative landscaping,