It is commonly used as a base for artificial lawns. When compacted it creates a secure base whilst still allowing for good drainage. Cracker dust is available at select landscape yards.
You will need to add a layer of compacted cracker dust as a substrate when installing artificial grass over sand. This stops movement underneath the artificial grass which would otherwise cause bumps. The cracker dust also provides a firm base to hold in your turf pegs. If installing over concrete, decking or pavers then cracker dust is not needed.
Road base is similar to cracker dust. However, road base contains a larger blue metal aggregate. The aggregate makes road base a very firm base when compacted. Some information on the web suggests using road base underneath your layer of cracker dust if you plan on parking on or driving over your artificial grass. If your top layer of cracker dust is 50-100mm deep, the 150mm u-shape turf pegs used to secure the edges of the grass will reach the layer of road base. The pegs can not be hammered into road base due to the aggregate and will bend.
To install cracker dust, you will need a plate compactor, screeding bars, concrete screed with level and/or soil spreader. All of these can be hired or bought from your local hardware store or landscape yard.
Existing sand will need to be excavated to a depth of around 100mm below finished floor level (FFL). FFL refers to the final level your grass will be at, usually determined by existing hard surfaces such as your alfresco area, pathways, driveways or doorways.
Not all areas have one, consistent FFL. If your area is sloped you will need to contour the area to meet all FFLs as gently as possible. For example installing in a front yard, your house may be elevated higher than footpath level. Your driveway might slope and the footpath may also slope up the road. You will not be able to use screed bars over an entire area that isn’t flat. Contouring an area can be difficult and done partly by eye.
Pile the cracker dust into the prepared area and distribute it to an even depth over your area with a concrete screed with level, screeding bars and/or soil spreader where possible.
We recommend using 70-100mm of cracker dust when installing artificial grass to allow for drainage and to secure the grass fully. However, cracker dust can be installed at a depth of 50-100mm depending on the intended use.
Wet the cracker dust thoroughly and compact with a plate compactor, filling any low points after the first compaction and compact again. After the first compaction, use a notched piece of timber to screed around the edges that are at finished floor level to ensure your artificial grass will sit evenly. On dry days we suggest you spray the cracker dust with a hose whilst you compact to reduce dust.
We recommend wearing earmuffs and steel cap boots when compacting.
Cracker dust is sold in cubic metres. Use the equation of square metres x cracker dust depth to calculate how many cubic metres you may need.
For example, an area that is 4 metres x 5 metres will be 20 square metres in size. If installing cracker dust to a depth of 70mm, use the equation 20 square metres x 0.07 to determine the cubic metre amount.
Alternatively, use a soil calculator, such as the one from Soils ain’t Soils.
Cracker dust is available at select landscape yards. Prices vary for supply and delivery. As a rough guide, you might expect to pay around $80 per cubic metre to collect. Check with your local landscape yard for pricing.