Artificial turf sits on top of several engineered layers, each serving a specific purpose. From the surface down, you’ll typically find infill material packed between the grass blades, a weed barrier fabric, a compacted stone or sand base, and the natural soil beneath it all. The exact setup varies depending on whether the turf is in a backyard, a sports field, or a playground, but the basic structure follows the same logic: drainage, stability, and cushioning.
Infill Between the Blades
The first thing hiding under the visible grass fibers is infill, a granular material packed between the blades to keep them standing upright and give the surface weight and stability. Without infill, artificial turf would lay flat and shift underfoot.
The most common infill options include:
- Silica sand: Affordable and widely available, silica sand works well for residential lawns with moderate foot traffic. It helps blades stand up and drains reasonably well, though it holds heat and can make the surface noticeably warm on hot days.
- Crumb rubber: Made from recycled tires, crumb rubber is the standard on sports fields because of its excellent shock absorption. It’s rarely used in home lawns because it retains heat, and the small black particles tend to track indoors.
- Organic infill: Coconut husk and cork infills are biodegradable alternatives that regulate temperature better than sand or rubber. The tradeoff is durability. They break down over time and need topping up more frequently.
The Weed Barrier
Directly beneath the turf backing, most installations include a geotextile weed barrier. This is a permeable landscape fabric that blocks weeds from pushing up through the surface while still allowing water to pass through. Installers typically overlap the seams by 6 to 12 inches and pin the fabric down with landscape staples or nails. In areas where the underlying soil tends to shift or become waterlogged, a second weed barrier may be placed even lower, underneath the stone base, to prevent soil from migrating upward into the aggregate.
The Compacted Stone or Sand Base
This is the most important structural layer and the one that determines whether the turf stays flat and drains properly for years. For a typical residential lawn, a bed of sharp sand (sometimes called paving sand) about 10 to 15 centimeters deep is often sufficient. The sand is leveled and compacted to create a smooth, firm surface.
For heavier-use areas like sports fields, driveways, or commercial installations, a two-layer base is standard. The bottom layer is 8 to 15 centimeters of crushed stone aggregate, topped with a thin finishing layer of sand (2 to 4 centimeters) for leveling. Crushed stone is the industry standard because its angular particles lock together when compacted, creating a stable surface that resists shifting. The tiny air pockets between the stones also allow water to flow through quickly.
Not all stone works equally well. Class II road base, a specific grade of crushed aggregate, is common in professional installations. Decomposed granite compacts tightly and creates a stable surface, but it doesn’t drain as well in areas with heavy rainfall. Pea gravel is one material installers actively avoid because its rounded shape prevents proper compaction, leading to uneven settling over time.
Lava granules are another option, available in finer grades that allow the entire base to be built and finished in a single layer rather than two.
Shock Pads on Sports Fields and Playgrounds
Sports fields and playgrounds often include an additional layer between the base and the turf: a shock pad. This is a separate sheet made of foam, rubber, polyethylene, or polypropylene that cushions impacts and reduces injury risk. Pads made from bound crumb rubber are particularly durable and can outlast the turf itself, sometimes serving through more than one turf replacement cycle. These heavier rubber pads are typically reserved for indoor use, while foam and polyethylene versions are more common outdoors. Residential lawns generally skip this layer unless the turf is being installed over concrete, where some cushioning makes the surface more comfortable.
Drainage Below the Surface
Water management is built into every layer. The turf backing itself is perforated to let rain pass through, and the infill and stone base are chosen specifically for their ability to move water downward and outward. On larger fields, a network of drains runs through the base layer, feeding into perimeter collector drains that connect to the site’s existing storm drainage system.
One detail that’s easy to overlook: how fast water moves through a turf system isn’t as straightforward as it sounds. Water tends to travel horizontally through the infill layer rather than dropping straight down through the turf backing. This means the drainage capacity of the base material matters more than the turf surface itself for preventing standing water after heavy rain.
What About Chemicals in the Layers?
There has been growing attention to PFAS (per- and polyfluoroalkyl substances, sometimes called “forever chemicals”) in artificial turf components. California’s Department of Toxic Substances Control has been investigating PFAS in turf products and published a technical document on the issue in early 2026. In response to regulatory pressure, the Synthetic Turf Council reported that its member manufacturers began working with their suppliers to remove all PFAS-based ingredients, including processing aids, from their products by 2025. California regulators are currently testing products to verify whether this industry shift has actually taken hold. If PFAS is still found in turf products, the state plans to move forward with formal regulation.
For homeowners researching turf, this means it’s worth asking manufacturers directly whether their backing, coatings, and infill are PFAS-free, particularly if the turf will be in an area where children or pets play.
The Full Stack, Top to Bottom
Putting it all together, here’s the typical sequence of layers from the surface down:
- Turf fibers and backing: The visible grass surface, usually made of polyethylene or polypropylene.
- Infill: Sand, rubber, or organic granules packed between the blades.
- Weed barrier: Geotextile fabric pinned in place.
- Shock pad (optional): Foam or rubber cushioning, mainly on sports fields and playgrounds.
- Compacted aggregate base: Crushed stone, sand, or a combination of both, typically 10 to 15 centimeters deep.
- Subsoil drainage (on large fields): Perforated drain pipes running to perimeter collectors.
- Native soil: The existing ground, graded to slope slightly for drainage before anything else goes on top.
The total depth of material between the grass tips and the original soil is usually somewhere between 10 and 25 centimeters, depending on whether the installation is a simple backyard lawn or a full athletic field with shock padding and engineered drainage.