When installing artificial turf in gardens, many people focus solely on the softness of the grass fibers and the realism of the color, while overlooking the invisible "respiratory system" lying beneath their feet. Although artificial turf does not require watering, moisture from the rainy season, morning dew, and occasional heavy downpours can still accumulate in the underlying layers. Without a proper drainage layer, water becomes trapped within the sand base and underlayment; over time, this leads to blackening at the turf seams, mold growth in the substrate, and-when walked upon-a distinct squelching sound or even a sensation of structural collapse.
A drainage board is a molded sheet made of high-density polyethylene (PE) featuring a distinct dimpled or textured surface structure. Its primary function is to utilize this three-dimensional support structure to create a stable air cavity, thereby establishing an "elevated drainage channel" situated between the soil and the paving surface. This design does not rely on the rate of water percolation; instead, it employs gravity-driven flow to rapidly channel accumulated water away laterally, thereby preventing root saturation, base layer softening, or structural damage caused by frost heave. In the context of rooftop gardens, the drainage board fulfills a triple role-providing waterproofing protection, acting as a root barrier, and facilitating a synergistic system of water retention and drainage-making it an indispensable structural component within modern lightweight greening systems.