Geocomposite is a manufactured product that combines two or more geosynthetic materials — typically a geotextile, geogrid, geomembrane or geonet — into a single composite engineered to deliver multiple functions simultaneously.
Main types of geocomposite
- Drainage geocomposites — a geonet or cuspated drainage core sandwiched between two non-woven geotextiles. Provides in-plane drainage capacity equivalent to 300+ mm of granular drainage stone.
- Reinforced geocomposites — a geotextile bonded to a high-strength geogrid. Combines separation, filtration and reinforcement in one product.
- Barrier geocomposites — geomembrane bonded to a protection geotextile, or geosynthetic clay liner (GCL) sandwiched between geotextiles.
- Erosion control geocomposites — three-dimensional polymer matrices combined with non-woven geotextile and seed mixes.
Drainage geocomposites in detail
Drainage geocomposites have largely replaced granular drainage in many UK applications because of the volume, weight and cost savings they deliver. A single 6 mm thick geocomposite layer can carry the same in-plane flow as 300 mm of clean drainage stone, removing the need to import large volumes of aggregate.
Typical applications include behind retaining walls, under bridge abutments, on landfill capping systems, beneath highways and around foundations. Hydraulic performance is specified per BS EN ISO 12958 (in-plane permittivity).
Design and specification
Geocomposite specification in the UK follows the relevant harmonised BS EN standards — BS EN 13252 for drainage, BS EN 13251 for reinforcement, BS EN 13361 for barriers. UKCA (with CE transitional acceptance) marking is required. Highways England Series 600 sets out approved usage classes for highway applications.
Long-term hydraulic capacity must allow for compressive loading and biological clogging — manufacturers provide reduction factors that engineers apply when sizing the product for the design life.
Related ViaCon solutions
ViaCon supplies geocomposites and the wider geosynthetic range — geotextiles, geogrids, geomembranes and GCLs — for complete drainage, reinforcement and barrier systems. See our geotechnical solutions. Related glossary entries: geotextile, geogrid, geomembrane and geosynthetic clay liner.
Frequently asked questions about geocomposite
What is a geocomposite?
A geocomposite is a manufactured product that combines two or more geosynthetic materials — typically a geotextile, geogrid, geomembrane or geonet — into a single integrated product. Composites deliver multiple functions (drainage, reinforcement, separation, barrier) simultaneously and simplify both specification and installation.
Can a drainage geocomposite replace granular drainage?
Yes — for most applications. A 6 mm thick drainage geocomposite typically delivers the same in-plane flow capacity as 300 mm of clean drainage stone. The savings in aggregate import, transport CO₂ and excavation depth are substantial. Behind retaining walls, behind abutments and beneath highways are the most common UK substitutions.
What standards apply to geocomposites?
UK specification follows the harmonised European standards: BS EN 13252 (drainage), BS EN 13251 (reinforcement), BS EN 13361 (barriers). UKCA marking is required (with CE transitional acceptance). Highways England Series 600 sets out approved usage classes for highway applications, including minimum tensile strength and in-plane flow capacity.
How long do geocomposites last?
UKCA-marked geocomposites are certified for a minimum design life under the harmonised standards — typically 25–100 years depending on application and exposure. Buried geocomposites protected from UV last well beyond their certified period: 100+ years is documented in many drainage and barrier applications.