Drainage system and method for artificial grass using spacing grid

A method for providing a drainage system for a synthetic grass turf assembly installed on a supporting soil substrate to provide a synthetic grass turf surface, the turf assembly including at least a plurality of upstanding synthetic ribbons of selected length, representing grass blades, extending upwardly from an upper surface of a flexible and water permeable sheet backing, the method comprising the steps of:

• a) preparing the supporting soil substrate in a slope;
• b) placing an impermeable membrane on top of the supporting soil substrate;
• c) placing a structurally self-supporting and flexible three-dimensional spacing device on top of the impermeable membrane, the spacing device having draining passages in both vertical and substantially horizontal directions throughout;
• and
• d) laying the turf assembly on top of the spacing device without performing any further preparation to the spacing device, the spacing device defining a spacing distance between the impermeable member and the sheet backing of the turf assembly, the draining passages permitting draining in both vertical and substantially horizontal directions at any elevation within the spacing distance.

A synthetic grass turf assembly for installation on a supporting soil substrate to provide a synthetic grass turf surface, the turf assembly comprising:

• a) a pile fabric with a flexible and water permeable sheet backing and a plurality of upstanding synthetic ribbons of selected length, representing grass blades, extending upwardly from an upper surface of the backing;
• b) an infill layer of particulate material disposed interstitially between the upstanding ribbons upon the upper surface of the backing and of a depth less than the length of the ribbons, the particulate material comprising at least one of hard and resilient granules, the infill including:
• i) a base course substantially exclusively of hard and resilient granules disposed upon the upper surface of the backing;
• ii) a top course substantially exclusively of resilient granules disposed upon the base course extending upwardly;
• and
• c) an impermeable membrane disposed on top of the supporting soil substrate;
• d) a flexible, structurally self-supporting three-dimensional spacing device elevating an undersurface of the backing away from the impermeable membrane and being disposed therebetween such that a spacing distance between the impermeable membrane and the undersurface is defined, the spacing device having draining passages in both vertical and substantially horizontal directions throughout the spacing distance such that water drainage both vertically and substantially horizontally is possible through the spacing device at any elevation between the backing and the impermeable membrane.