What do you put under artificial grass?

In the laying of artificial turf, many people tend to only focus on the quality and appearance of the grass on the surface, but ignore the basic structure "under the feet". In fact, the laying of the underlying foundation is not only the supporting core of the entire lawn system, but also directly affects its service life, drainage performance, comfort and later maintenance costs.

1. Base structure: the foundation of stability and support

Common materials:

gravel, broken bricks, coarse sand, stone powder, concrete, etc.

Function:

• Provide a stable and flat support surface to prevent the lawn from being uneven;
• Enhance the overall bearing capacity of the lawn to avoid sinking or deformation during use;
• Ensure that the lawn system can maintain structural integrity during long-term use.

Benefits:

Strengthening the foundation can increase the service life of the lawn and reduce the cost of later repairs and re-paving. It is especially suitable for public areas and sports venues with large traffic.

2. Drainage system: ensure dryness and mildew prevention

Common forms:

Natural drainage layer (gravel layer); Drainage ditch or seepage hole; Pad slope design

Function:

• Quickly drain rainwater to avoid water accumulation;
• Prevent water from accumulating in the bottom layer, causing mold and rot;
• Improve the availability of lawns after rain or in humid environments.

Benefits:

Improve the comfort of use and the dryness of the lawn, especially in outdoor or rainy areas, to ensure all-weather use.

3. Weed prevention layer: ensure beauty and low maintenance

Material:

high-density non-woven weed prevention film

Function:

• Effectively block weeds from drilling out of the surface;
• Keep the lawn surface clean and beautiful;
• Reduce maintenance frequency and weeding costs.

Benefits:

Reduce the aesthetic problems and safety hazards caused by weed growth, especially suitable for landscape lawns and garden sites.

4. Buffer layer (optional): Provide sports comfort

Applicable scenarios:

football field, basketball court, running track, children's playground, etc.

Common materials:

rubber pad; EVA foam pad; elastic pad

Function:

• Absorb impact and reduce the pressure of exercise on joints;
• Improve ground elasticity and enhance sports experience;
• Reduce the risk of sports injuries.

Benefits:

Provide a safe and comfortable sports environment, especially suitable for high-intensity use or children's activity areas.

5. Site Assessment and Planning

Before laying artificial turf, a site assessment and planning are necessary.

(1) Existing Subgrade Diagnosis

• Surface Type: Is it native soil, old turf, old hardened layer (cement, asphalt), or construction backfill?

• Assess Soil Properties: Conduct a simple "water seepage test"—dig a pit approximately 30 cm deep, fill it with water, and observe the time required for it to completely drain. If it takes more than 4 hours, it is considered poorly drained clay soil, requiring a more robust drainage design.

• Check Levelness: Use a long straightedge or string line to check the existing ground leveling and estimate the amount of earthwork required.

(2) Planning and Construction

a. Site Clearing and Positioning

• Operation: Remove weeds, gravel, garbage, and other debris from the site; level the existing ground; determine the site boundaries, slope, and functional areas according to the design drawings.

• Key Requirements: The existing ground should have no obvious protrusions/sinks; a preliminary slope should be reserved to avoid leaving sharp debris.

b. Foundation Construction

1) Existing Ground Treatment

Compact the cleared site to prevent later settlement; if the soil is loose, lay a 10-15cm thick layer of graded gravel and compact it again.

2) Drainage System Construction

• Surface Drainage: The foundation should have a 1-2% slope to ensure natural rainwater flow and prevent water accumulation.

• Underground Drainage: Lay drainage blind ditches (using gravel + perforated drainage pipes) in the foundation base layer, or reserve drainage channels in the graded gravel layer, with the drainage pipes connected to the municipal drainage system.

3) Base Layer Laying

• Lay a 15-20cm thick layer of graded crushed stone and compact it.

• For sports fields, lay a 5-8cm thick cement-stabilized layer on top of the crushed stone layer. Cure for 7-10 days until the surface reaches the required strength and is free of sand and cracks.

c. Weed Control Fabric Laying

• Procedure: Fully cover the compacted base surface with weed control fabric, overlapping each layer by 10-15cm. Secure with U-shaped nails to prevent displacement.

• Purpose: Prevents weeds from penetrating the lawn from under the base and prevents gravel particles from rising and contaminating subsequent layers.

• Note: The weed control fabric must cover the entire construction area, extending 5-10cm beyond the field boundary to ensure no areas are missed.

d. Buffer Layer Installation

• Procedure: Lay the buffer layer fully over the weed control fabric, ensuring the planks are tightly joined and secured with special adhesive or U-shaped nails.

• Function: Improves foot comfort, reduces impact during exercise, protects joints, and enhances the overall elasticity of the lawn.

• Applicable Scenarios: Required for sports fields and kindergarten grounds; optional for residential landscape lawns. If the foundation is flat and a minimalist design is desired, this step can be omitted, and the lawn can be laid directly.

• Acceptance Standards: The buffer layer should be laid flat, without arching or wrinkles, firmly fixed, and should not shift when walked on.

6. Why bother installing artificial turf?

While artificial turf is more troublesome initially, its long-term advantages completely outweigh the initial investment, making it the preferred choice for sports fields, commercial spaces, and home gardens. Its advantages are particularly prominent for users seeking "worry-free, durable, and cost-effective" options.

• Extremely low long-term maintenance costs

Natural turf requires frequent watering, mowing, fertilizing, and replanting, with annual maintenance costs approximately 3-5 times that of artificial turf. It is also prone to becoming muddy in rainy weather and turning yellow in sunny weather. Artificial turf requires no maintenance, only regular simple washing, and has a lifespan of 8-15 years, saving significant time, manpower, and money in the long run.

• All-weather use

Unaffected by weather, it does not accumulate water in rainy weather or generate dust in sunny weather, allowing for continuous 24-hour use, especially suitable for high-frequency use scenarios such as school playgrounds and sports stadiums.

• Wide Adaptability

Adaptable to various scenarios, from professional football fields and running tracks to commercial areas, kindergarten activity areas, and family courtyards. Simply select the appropriate grass height, density, and material according to your needs; there's no need to worry about soil conditions or climate limitations.

• Safe and Environmentally Friendly & Stable Performance

High-quality artificial turf uses PE material, passing authoritative environmental certifications such as EU REACH, and is formaldehyde-free and odorless. The grass fibers are soft and have a cushioning layer design, effectively reducing sports collision injuries while avoiding the pesticide residues and mosquito breeding problems that may exist with natural turf.

• High Cost-Effectiveness

Although the initial installation cost is higher than natural turf, its lifespan of over 8 years and extremely low maintenance costs make it far more cost-effective than natural turf. Furthermore, the grass has a uniform color and a neat appearance, and it won't turn yellow with seasonal changes, maintaining its evergreen and beautiful appearance for a long time, making it especially suitable for commercial spaces or family courtyards where a high image is required.

7. Scientific laying, twice the result with half the effort

Although the surface of artificial turf is important, it is the "invisible" underlying structure that really determines its performance. Scientific and reasonable ground foundation design is not only the basis for ensuring beauty and durability, but also the key to improving the user experience and reducing later maintenance.

Whether it is a residential garden, park landscape, or professional sports venue, the correct underlying laying will lay a solid foundation for your project and achieve multiple goals of beauty, practicality and economic benefits.

If you need to customize the underlying structure plan for different scenarios (family, business, sports, etc.), please contact our UNIGRASS team, we will provide you with professional turf foundation design and construction suggestions.

FAQ

Q: Can I lay new artificial turf directly on top of old turf?

A: Not recommended. The old turf and base layer must be completely removed, the soil base inspected and repaired, and then the turf should be re-laid. This is the only way to ensure drainage and durability.

Q: Will it flood after rain?

A: As long as the "sandwich" structure of the base layer, especially the gravel layer and slope, is constructed correctly, the drainage speed will be much faster than natural turf, and it can be used within minutes after rain.

Q: Can I lay it directly on sand?

A: Sand has good but unstable drainage. It needs to be fully compacted on the sand first, then a layer of geogrid is laid for reinforcement, and then the standard structure such as the gravel layer is laid.