A good drainage system is more than simply giving the surface a slope.

The complete system may include:

surface slope + permeable layers + drainage channels + perimeter drainage + subsoil drainage

Depending on the design, surface gradients around 0.2%–0.5% may be encountered in sports-field projects, but the actual slope must be determined by the engineering design and the requirements of the selected turf system.

The critical requirement is that the slope should be:

• Consistent
• Free from sudden changes
• Connected to an effective drainage system
• Designed to prevent localized ponding

A drainage slope that looks correct on paper can still fail if the underlying drainage system has insufficient capacity.

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10. Don’t Install Turf on a Wet or Unstable Base

This is particularly important for adhesive-backed installations.

Before installation, the contractor should verify the base condition specified by the turf and adhesive manufacturer.

Depending on the system, relevant checks may include:

• Surface moisture
• Relative humidity
• Concrete moisture condition
• Surface temperature
• Ambient temperature
• Cleanliness
• Surface strength

There is no universal moisture percentage that applies to every turf adhesive.

For example, a manufacturer’s adhesive may have a specific maximum substrate moisture requirement, while another system may use a different measurement method.

Therefore:

Always follow the adhesive manufacturer’s technical data sheet rather than applying a generic “≤8% moisture” rule to every project.