Artificial grass looks stunning, but what sits underneath determines the final result. Poor base preparation can cause low spots, uneven sections, and water pooling after rain. 

Melbourne residential sites don’t behave the same way. One backyard may have dense clay, while another may stay wet after heavy rainfall. Foot traffic and site slope can also change what is required. Therefore, consider artificial turf as part of a complete installation, not just a surface rolled over existing soil. Choosing suitable base materials gives the lawn a much better foundation. 

What Goes Under Artificial Grass? Start With the Right Foundation

An artificial grass installation over natural ground usually consists of several prepared layers. After existing grass, roots and unsuitable material are removed, the ground is excavated to the required level.

Install and compact a structural sub-base. A finer material may be placed above it to create a smoother surface for the turf. Depending on the site, a weed membrane or additional drainage solution may also form part of the installation.

Each layer has a different job. Trying to make one material do every job can affect drainage, stability, or the finished level.

Layer 1: Do You Need a Weed Membrane Under Artificial Grass?

A weed membrane can help reduce unwanted vegetation growing up through an artificial lawn, particularly when turf replaces an existing garden or natural grass area.It should not, however, be viewed as a substitute for proper ground preparation. You still need to remove existing vegetation and roots before building the base.

The location of the membrane can also depend on the installation. Pet areas may need special drainage and cleaning considerations, so instead of treating every backyard the same with regard to the base system, consider treating this area differently.

Layer 2: What Is the Best Sub-Base for Artificial Grass?

Sub-base is the real strength under the grass. It needs to stay solid underfoot while allowing the surface to slope naturally and drain water away. Graded crushed rock and a variety of road-base materials are often included because they contain particles of varying sizes that form a strong layer when compacted, and their angular edges interlock more firmly than rounded gravel. 

This layer can be especially critical for larger lawns and high-traffic areas, although you’ll want to test and prep the existing ground before deciding whether to incorporate aggregates.

Crushed Rock or Road Base: Which Works Better Under Artificial Turf?

Every site needs different base materials. The best material can range from high-quality granular material to soil with specific grading, compaction properties, drainage requirements, and underlying ground conditions.

Road base can provide a strong foundation where stability is the priority. Certain crushed-rock products may also offer a useful combination of drainage and compaction. Other locally available crushed products, including mudstone, may be considered for landscaping applications where their specifications suit the job. Rather than choosing according to the product name alone, check whether the material is recommended for the required base application.

Can You Use Stone Dust Under Artificial Grass?

Stone Dust can be useful when a finer material is required above the structural sub-base. Its small particles are relatively easy to spread, allowing installers to correct minor variations and prepare a smoother surface before laying turf.

The important distinction is between a levelling material and a structural base. Stone dust should not automatically replace the deeper compacted layer beneath an artificial lawn.

Drainage also needs attention because very fine crushed materials behave differently from coarse aggregate. If you are looking for stone dust for sale, tell the supplier the intended application rather than ordering based only on price or quantity.

Layer 3: What Should You Use for the Levelling Layer?

Once the structural base is compacted, prepare the surface for the turf. Small bumps or depressions left at this stage can become noticeable after the artificial grass has been installed.

A suitable fine crushed material or coarse sand may be used as a thin levelling course, depending on the installation specification. You can screed it across the surface to establish a consistent finish and the required fall. The goal is not to create another thick structural layer. It is to provide a smooth transition between the compacted base and artificial turf.

Sand vs Stone Dust Under Artificial Grass: What’s the Difference?

Both materials can help level the ground, but they behave differently.

Suitable coarse or sharp sand can be easy to spread and screed. Fine crushed rock products can form a firmer surface after preparation. Their drainage characteristics also differ, so the existing ground and sub-base need to be considered.

It is also important to distinguish base sand from the infill that may later be brushed into artificial grass fibres. If you are unsure about the required grade, experienced Sand suppliers can help identify a product suitable for the intended landscaping application.

How Deep Should the Base Be for Artificial Grass?

There is no reliable universal depth for every artificial lawn. The required depth depends on ground stability, drainage, expected traffic, the chosen base material and the finished height around paths, garden edging and other surfaces.

A heavily used family backyard, for example, may have different preparation requirements from a narrow decorative strip beside a driveway. Before purchasing bulk material, confirm the required excavation and compacted base depth with your turf installer or landscape professional. This also makes quantity calculations more accurate.

Extra Drainage: When Does an Artificial Lawn Need It?

Artificial grass is designed to allow water through, but that water still needs somewhere to go.

If the ground underneath drains slowly, installing permeable turf alone will not necessarily solve the problem. Low sections of a property, compacted ground and clay-rich soil can all influence water movement.

Check the area after rainfall before beginning work. Water that regularly sits in the same location is a useful warning sign. Some sites may require drainage improvements, changes to the base design or better surface falls before turf is installed.

How Melbourne Ground Conditions Affect What Goes Under Your Turf

Melbourne’s residential properties can have quite different ground conditions, even within the same broader area. This makes site assessment more useful than copying the base used at another property.

Pay attention to how quickly the existing ground dries, where runoff travels and whether the area becomes soft after rain. Also check the finished level in relation to paths, patios and buildings. These observations can help determine whether the project needs greater emphasis on drainage, stability or both.

How Much Base Material Do You Need?

For a rectangular area, volume can initially be estimated using:

Length × width × required depth = cubic volume

When ordering in cubic metres, all measurements need to be converted to metres. A 50 mm layer, for example, should be entered as 0.05 m in the calculation. Remember that loose aggregate settles as it is compacted. 

Excavation levels, material type and site conditions can therefore affect the quantity ultimately required. Confirming the compacted depth before ordering can help minimize waste and material shortages.

Choose the Right Base Material for Your Project Before Ordering 

Cost matters, but don’t choose the cheapest base material unless it meets your needs. Consider the project first. What’s the approximate size, current ground conditions, drainage, the depth of your base and whether the space will be used by people or pets? 

This helps your landscape material supplier recommend the right product and quantity. Building Garden Supplies Melbourne provides materials for landscaping and outdoor living projects, including sub-base and levelling materials.

A Better Artificial Lawn Starts Below the Surface

Choose the best quality artificial grass, but remember: all good-quality turfs must be laid on a sound surface. A stable sub-base, an appropriate finishing layer, and effective drainage create a smooth surface and keep water from becoming an ongoing issue. Always take stock at the outset, determine the base specification, and work out the material quantity needed before ordering. Underlying materials may be out of sight by the time you finish the job, but not out of mind.

FAQ

Q. What is the best thing to put under the artificial grass?

A. Basically, a multi-layer foundation starting with a geotextile membrane to block weeds and followed by a two- to four-inch compacted sub-base of properly graded and compacted crushed rock for stability and drainage. Choose appropriate specifications based on site and turf installation requirements. 

Q. What is the best base material for artificial grass in Australia?

A. A properly graded and compacted layer of crushed rock such as road base or decomposed granite topped with finer dust is best. 

Q. What are the common problems with artificial grass?

A. Common problems include poor drainage, water pooling, uneven or sinking areas, weed growth, and flattened fibres. Many of these issues can result from improper ground preparation and installation. 

Q. What type of sand is best for a base for artificial turf?

A. Coarse or sharp sand is often used as a levelling layer beneath the turf. It should be a suitable grade to create a stable, uniform surface while still ensuring adequate drainage. 

Q. How do I prepare the ground for artificial grass?

A. Remove existing grass, weeds and loose material, excavate the area as required, and prepare a properly compacted sub-base. Finish with a suitable levelling layer and ensure the surface has adequate drainage before laying the turf.