GeoDrain Dimpled Drainage Boards & Geocomposites

GeoDrain dimpled drainage boards and geocomposites provide a defined drainage and protection layer behind below-ground structures and beneath landscaped roof systems. The profiled HDPE core creates a continuous void through which collected water can be conveyed to the designed drainage outlet, while protecting the waterproofing system from direct contact with soil, backfill and construction loads. GeoDrain systems are used for basement walls, retaining structures, foundations, underground parking, podium decks, planter boxes and green roofs.

The GeoDrain range is deliberately focused around the performance classes commonly encountered on South African civil and building specifications. DS 8-600 and GEO 8-250 provide 8 mm profiles with 250 kN/m² compressive resistance for standard protection and drainage applications; GEO 10-400 provides a 10 mm, 400 kN/m² high-performance geocomposite for more demanding structural drainage; and GR 20/200 provides a 20 mm, 200 kN/m² perforated drainage and water-storage layer for vegetated roof systems. This focused range allows engineers and contractors to select by required function, compressive class and drainage configuration rather than by brand name alone.

For high-volume basement, foundation and retaining-wall work, GeoDrain offers two 8 mm / 250 kN/m² configurations. DS 8-600 is a bare HDPE dimpled protection sheet for applications where a durable separation, protection or drainage cavity is required without an integral filter layer. GEO 8-250 combines the dimpled HDPE core with a factory-bonded polypropylene filter geotextile, allowing water to enter the drainage void while restricting migration of surrounding soil fines. The choice between DS and GEO should therefore be based on the required filtration function, not compressive strength alone.

GeoDrain GEO 10-400 is the flagship civil drainage geocomposite for higher-load and higher-capacity applications. Its 10 mm HDPE drainage core provides 400 kN/m² compressive strength and is factory-bonded to a polypropylene filtration geotextile. The current technical specification reports an in-plane water-flow capacity of 4.11 × 10⁻³ m²/s at 20 kPa and hydraulic gradient i = 1.0. GEO 10-400 is suited to deep basements, retaining structures, underground parking, podium construction, tunnels and other civil works where both drainage and filtration must remain functional under significant imposed loading.

For green roofs and landscaped podiums, GeoDrain GR 20/200 is a perforated 20 mm HDPE drainage and water-storage board designed to manage both temporary water retention and excess rainfall. Reservoirs within the profiled sheet store approximately 6.0 L/m² of water for the planted build-up, while excess water drains through the perforations toward the roof drainage system. GR 20/200 provides 200 kN/m² compressive strength and a published drainage capacity of 10.6 L/s·m. A suitable filter geotextile is installed above the board before placement of the growing medium where required by the system design.

GeoDrain is supplied with technical support for specification, product selection and approved-alternative submissions. Engineers, quantity surveyors, waterproofing contractors and main contractors can submit an existing drainage-board specification, BOQ or competitor datasheet to Geosynthetics Africa for a line-by-line technical compliance review covering dimple height, compressive resistance, drainage performance, filtration configuration, material and roll dimensions. Products are stocked in South Africa for project supply, with technical documentation available for consultant approval and distribution support across sub-Saharan Africa.