In brief
On soil or old lawns, artificial grass requires a compacted, water-permeable foundation: approximately 8–12 cm of excavation, a gravel base layer of 5–8 cm, a 2–3 cm leveling layer made of grit or crushed sand, and a weed membrane. On solid surfaces such as concrete, pavement, or tiles, the gravel is not required – here, the slope and a drainage or leveling mat are crucial.
The sub-base is the foundation of every artificial grass surface. Mistakes made here can hardly be corrected later: dents, ripples, puddles, and weeds almost always originate in the foundation. We show you which structure is right for which sub-base and how to calculate material quantities.
Which sub-base requires which structure?
| Sub-base | Structure | Important |
|---|---|---|
| Soil, old lawn | Excavation, gravel base layer, leveling layer, weed membrane | Compaction and slope |
| Concrete, screed | Drainage or leveling mat if necessary, artificial grass | Water drainage, check for cracks |
| Pavement | Leveling mat, artificial grass | Joints must not show through |
| Tiles, terrace | Drainage mat, artificial grass (loose or glued) | Slope towards the drain |
| Balcony, roof terrace | Drainage mat, artificial grass (loose-laid) | Protect waterproofing, weight, wind suction |
| Wooden deck | Only after inspection, with rear ventilation | Moisture can damage wood |
The classic foundation in the garden
On soil, a professional foundation consists of several layers:
| Layer | Material | Thickness (guide value) |
|---|---|---|
| Artificial grass | e.g., Royal Grass® | – |
| Weed membrane | water-permeable geotextile | – |
| Leveling layer | Crushed sand or high-grade grit, e.g., 0/5 or 2/5 | approx. 2–3 cm |
| Base layer | Gravel, e.g., 0/32 | approx. 5–8 cm |
| Subgrade | natural, compacted soil | – |
Step by step
- Excavation: Remove lawn, roots, and topsoil to a depth of approx. 8–12 cm – see excavation.
- Compact the subgrade: Level the exposed soil and compact it with a vibratory plate compactor.
- Install edging: Install lawn edges or border stones before the gravel.
- Install base layer: Apply gravel in layers and compact it.
- Screed the leveling layer: Level precisely with a straightedge, plan for a slight slope, and re-compact.
- Lay weed membrane: with approx. 10 cm overlap.
Calculate material requirements
For an initial estimate, multiply the area by the layer thickness. Example for 50 m²:
| Layer | Calculation | Volume |
|---|---|---|
| Excavation (10 cm) | 50 m² × 0.10 m | 5.0 m³ |
| Gravel (6 cm) | 50 m² × 0.06 m | 3.0 m³ (compacted) |
| Crushed sand/grit (2.5 cm) | 50 m² × 0.025 m | 1.25 m³ (compacted) |
Since loose material settles during compaction, a surcharge is included when ordering. Your building material supplier will provide the appropriate values for the respective material.
Artificial grass on concrete, pavement, and tiles
Solid surfaces are already load-bearing but do not drain water downwards. Therefore:
- Check the slope – water must be able to flow to the edge or drain
- A drainage mat creates space for water runoff and levels out small unevenness
- Bridge joints and edges in pavement with a leveling mat
- On roof terraces, never damage the waterproofing and consider wind suction
The most common foundation mistakes
| Mistake | Consequence |
|---|---|
| Insufficiently compacted | Dents and hollows after a few months |
| Leveling layer too thick | Material shifts, surface becomes uneven |
| No slope | Puddles, moss, odors |
| Wrong material, e.g., rounded gravel | Hardly possible to compact |
| Forgot weed membrane | Weeds grow through from below |
Our offer
We inspect your sub-base on-site and handle the foundation and installation from a single source – nationwide. More about artificial grass installation. To see what happens next, view our step-by-step guide.
Frequently asked questions about artificial grass sub-bases
Which sub-base is best for artificial grass?
In the garden, a compacted foundation made of gravel and a leveling layer of crushed sand or grit with a weed membrane is best. On solid surfaces like concrete or tiles, a drainage mat is suitable, provided there is a sufficient slope.
How thick should the foundation for artificial grass be?
In private gardens, approximately 5 to 8 centimeters of compacted gravel and 2 to 3 centimeters of leveling layer are typical. For poor soil or higher loads, the base layer is reinforced.
Can artificial grass be laid on sand?
Pure sand as the only layer is not sufficiently load-bearing and will shift. Crushed sand or high-grade grit are better suited as a thin leveling layer on a compacted gravel base layer.
Can artificial grass be laid directly on pavement?
Yes, this is possible on level pavement with a slope. To prevent joints and edges from showing through and to allow water to drain, a leveling or drainage mat is recommended underneath.