Find out the best sub-base for artificial grass
The Best Sub-Base for Artificial Grass: A Comprehensive Guide
When it comes to an artificial grass installation, one of the most critical components to ensure longevity and performance is the artificial grass sub-base (what you install it on top of). This foundation plays a vital role in providing structural stability, proper drainage, and a smooth surface for your synthetic lawn, get it wrong and you’ll get lumps, bumps and likely have to redo the sub-base again quite soon. Whether you’re working on a backyard putting green or a new lawn, choosing the best sub-base for artificial grass is crucial, so let’s look at the options…
What is a Sub-Base and Why Is It Important?
The sub-base is the layer beneath the artificial grass base that provides a solid foundation and structural support for the turf. It helps to prevent uneven surfaces, enhances drainage, and ensures that your artificial lawn remains smooth and durable under foot traffic for years of use. Without a proper sub-base, your synthetic grass installation may suffer from drainage issues, shifting, and an overall decrease in the quality of your artificial grass. I’ve read lots of reports from people who tried to get away with laying on top of sand or simply topsoil without levelling and compacting and they all rue their mistake as taking the easy option created more work in the long run.
Best Sub-Base for Artificial Grass
Several sub-base options are available, each catering to different specific needs and site conditions. Here are the most commonly used materials in professional artificial grass installations:
- Crushed Miscellaneous Base (CMB)
CMB is one of the most popular choices for a good base in artificial turf installations in the US. It’s a gravel mixture consisting of crushed concrete, asphalt, and other materials. This mix offers excellent structural stability and superior drainage, making it an excellent choice for most synthetic turf installations. In the UK, ballast is probably the most comparable product and is available in smaller bags or huge bags from the DIY store or builder’s merchant. - Crushed granite aka Grano Dust
Grano dust is available in huge bulk bags and is an ideal sub-base for artificial grass because it is hard, compactable and forms a strong and resilient layer that is permeable and not prone to movement. It consists of small pieces of granite rock, which compact well to create a stable layer. It’s especially favoured in areas requiring a smoother finish. - Mot Type 1
Mot Type 1 is another high-quality sub-base material known for its stringent testing and durability. It’s composed of crushed limestone or granite, making it an excellent choice for areas with heavy foot traffic or where drainage issues are a concern. (We used this as a base for a DIY path I laid down the side of our house and it was brilliant. - MOT Type 2
MOT type 2 is similar to type 1 but is comprised of smaller pieces of rock.
What not to use for a base for artificial grass
- Gravel
Although it seems like a good idea, round pea gravel isn’t ideal as a sub-base because all the stones are of a similar size and shape and are rounded meaning they slip and slide around making compacting all the harder. You could mix the gravel with sharp sand to create your own version of a ballast or MOT style base but it will be more expensive that buying the correct one. - Sand
Whilst sand is good for a thin layer on top of your sub-base, directly under your artificial grass (for comfort under foot) it isn’t good on its own as a thicker sub base layer as it doesn’t compact enough and will be liable to movement so you’ll likely end up with lumps and bumps visible in your artificial turf surface.
Preparing the Area
Before installing the sub-base, it’s essential to prepare the project area. This involves removing natural grass, sprinkler systems, and other obstructions. Next, the native soil must be compacted to create a solid surface. Professional installers often use a plate compactor to ensure the entire area is well-compacted and ready for the base layer.
- Begin by laying down a layer of aggregate, typically 2-3 inches deep. This forms the initial solid base on which the artificial turf will sit. Crushed stone or pea gravel is often used at this stage, providing a smooth foundation and aiding in proper drainage.
- Once the aggregate is in place, it’s crucial to compact it using heavy machinery like a plate compactor. This step ensures that the artificial grass sub-base is stable and resistant to shifting over time.
- Installing a weed barrier or weed membrane on top of the compacted sub-base helps prevent weed growth, ensuring that your fake grass remains pristine. This is an essential step in the whole process, especially in areas prone to weeds.
- A final layer of limestone dust or grano dust may be added to achieve a smoother finish. Sharp sand can be applied here but This provides the perfect surface for laying the turf rolls and ensures a smooth surface for the synthetic grass.
Don’t forget Drainage!
Proper drainage is critical in preventing water accumulation under the turf, which can lead to drainage issues. Ensure that the sub-base is designed with a slight gradient to allow water to flow away from the synthetic lawn. Landscape fabric or privacy policy fabric may be laid underneath to further assist with drainage and weed control.
Conclusion
Selecting the right sub-base for your artificial grass project is one of the most important steps in achieving a durable, aesthetically pleasing, and low-maintenance synthetic lawn. Whether you’re using crushed miscellaneous base, granite dust, MOT Type 1 or 2 or ballast, ensuring that your artificial grass sub-base is properly prepared and installed is key to the quality of your artificial grass. By following these guidelines, you can create a solid foundation that will support your synthetic turf for years of use and keep it looking as good as new.
