Drainagekern

Drainagekern is a term used in civil engineering and geotechnics to describe the central, porous core of drainage systems and drainage boards. It acts as a water storage and conveyance layer, enabling infiltrated water to move away from structures or soil while reducing hydrostatic pressure on foundations and walls.

Materials and structure vary, but common implementations use molded plastic foams or honeycomb-like cores made from polyolefins (such as polyethylene or polypropylene) or recycled plastics. The core is typically protected by geotextile or filter sheets on both sides to prevent soil fines from clogging the pores, while allowing water to pass through freely. The overall assembly may be installed as panels, mats, or modular units.

Applications include foundation and retaining-wall drainage, sub-surface drainage layers under roads or pavements, green roofs, and drainage blankets in landscaping. In green roofs, the drainagekern enables excess rainfall to be collected and guided to outlets, supporting plant health and roof longevity. In basements and tunnels, it helps relieve pore-water pressure and improve drying.

Key properties are high permeability, light weight, mechanical stability, chemical resistance, and compatibility with soils and filters. Selection depends on porosity, thickness, load exposure, temperature, and compatibility with accompanying geotextiles or membranes. Installation requires proper separation from the soil, attention to edge connections, and ensuring a clear drainage path to outlets.

See also: drainage layer, geotextile, drainage board, green roof.