Proper ground preparation is crucial to ensure a successful and long-lasting artificial grass installation. Here are some tips on preparing your ground for artificial grass, depending on the type of surface you are working with.
On Existing Grass First, the existing grass needs to be removed to 40 mm or the depth of the existing roots. The ground should be levelled, and soft spots should be filled with hardcore. Next, excavate the foundation for the correct construction depth so that the grass finishes with the fibres 20 mm higher than the finished surface’s edges.
Once the formation layer is firm, spread, level, and compact 35 mm of sharp sand to the desired gradients. If the formation layer is “boggy,” you may need more excavation and a 100 mm layer of hardcore. However, if the surface area is hollow and the water doesn’t drain away, adding artificial grass and sand layers may not solve the drainage problem.
On Tarmac If you’re laying artificial grass over tarmac playgrounds or tarmac tennis courts, you should fill any hollows with sand and cement. Remove any large weeds and, if necessary, spray the weed with a total trans-located herbicide. Artificial grass can be laid directly over the Tarmac and fixed at the edges. However, the grass can feel hard when laying artificial grass over Tarmac. To avoid this, lay a 10 mm shock-safe Play pad under the artificial grass. This also helps with rapid surface water drainage.
When laying over Tarmac, you may encounter inspection chamber covers requiring access. You have several options here:
Regarding standing water, sometimes it is possible to drill the Tarmac with 30-50mm diameter holes at one-meter centres, backfilling them with a pea shingle. (The porosity of the sub-base must be checked before drilling.)
On Roof Tops Often, rooftops have waterproof barriers that cannot be fixed. The recommended way to fix artificial grass on rooftops is to weigh it down. Spread 10 kg/m2 of silica sand into the grass pile to do this. Specific roof systems will require a separating membrane between the artificial grass and the waterproof system. A geotextile membrane, such as Terram 1000, is often used.
Over Existing Wet Pour If you’re laying artificial grass directly over the existing wet pour, any hollows or deep cracks should be filled with rubber crumbs and binder. The perimeter of the artificial grass can be fixed using one of the various options.
Over Steep Mounds Mounds should be constructed from MOT type 1 crushed stone shaped, levelled, and compacted in 150 mm layers. The stone’s surface should be covered in a 50 mm depth of C25 concrete screed, smoothing the concrete to gradual slopes.
However, it is impossible to wrap a curved mound in a shock pad to enhance critical fall height. Areas where a CFH is required, should be designed to accept flat sheets of shock pad with a very gentle one-dimensional curve at most. These areas can still be sloping.
Over Steep Slopes > 30 Degrees First, remove the existing grass to a depth of 40 mm or the depth or the roots’ depth. The ground should be levelled, and soft spots should be filled with hardcore. Next, excavate the ground to allow for the correct depth of construction so that the grass finishes with the fibres.
