Drainage Gravel (40mm)

Drainage Gravel is a versatile aggregate that can be used for both decorative and practical applications. Its free-draining properties make it an excellent choice for diverting water and improving drainage, often in conjunction with other drainage systems.

Drainage Gravel is commonly used for:

• French drains
• Retaining wall drainage
• Trench drainage
• Agricultural drains
• Pipe backfilling
• Soakwells
• Garden drainage

Choosing the right size Drainage Gravel depends on your application. Here are our recommendations for the gravels we stock:

5-7mm Drainage Gravel (Pea Gravel): Great as a decorative option for pots and gardens. It is also ideal for tight access areas, bedding around sewer and in-ground plumbing, and other small drainage applications.

10mm Drainage Gravel: A great choice for residential projects such as backfilling around AG pipe, water diversion on sloping areas, and subsoil drainage.

20mm Drainage Gravel: Perfect for backfilling behind retaining walls and other high-flow areas where larger volumes of water need to be moved.

40mm Drainage Gravel: Best suited to heavy-duty commercial applications, including deep trenches, large soakwells, and on-site water diversion.

To calculate how much Drainage Gravel you need for your project, measure the length and width of the area where the gravel will be placed.

Next, determine the desired depth of the gravel. The required depth will vary depending on your project and the area you need to fill.

Once you have your length, width, and depth measurements, you can use our cubic metre calculator above or calculate the volume manually using the following formula:

Volume = Length × Width × Height

Note: We recommend adding at least 10% extra to your total calculated volume to allow for settling and levelling.

While not essential for every project, we highly recommend using Bidum filter cloth (geofabric) and AG pipe alongside your drainage gravel. The geofabric helps prevent soil from washing into the gravel, while the AG pipe efficiently collects and carries water away. Together, they create a more reliable, longer-lasting drainage system and help reduce future maintenance.