Geotextile — GeoTechnical Solutions

Geotextile is a permeable textile manufactured from synthetic fibres — typically polypropylene or polyester — used in contact with soil or other materials in civil engineering applications. Geotextiles fulfil five primary functions defined under BS EN ISO 10318, and a single fabric often delivers two or more of these simultaneously.

The five primary functions

BS EN ISO 10318 defines the standard functions that any geotextile may be specified to perform:

• Separation — prevents intermixing of dissimilar soil layers (typical: between subgrade and aggregate sub-base).
• Filtration — allows water to pass while retaining soil particles (drainage applications).
• Drainage — transmits water along the plane of the fabric (e.g. behind retaining walls).
• Reinforcement — resists tensile stress and improves load-bearing capacity of soil (specialist reinforcement geotextiles).
• Protection — prevents mechanical damage to geomembranes, root barriers and other vulnerable layers.

Woven vs non-woven geotextiles

The two principal manufacturing types have substantially different properties and applications:

Property	Woven	Non-woven (needle-punched)
Tensile strength	High	Medium
Permittivity (water flow)	Low to medium	High
Filter performance	Limited	Excellent
Typical UK use	Reinforcement, separation under heavy loads	Filtration, drainage, protection

UK specification standards

Geotextiles for UK applications must carry UKCA marking (with CE marking transitional acceptance) under the relevant harmonised standards: BS EN 13249 (roads), BS EN 13251 (earthworks), BS EN 13252 (drainage) and others. Highways England Specification Series 600 sets out approved usage classes; class designation determines minimum tensile strength, CBR puncture resistance and characteristic opening size required for separation under aggregate sub-bases.

For SuDS infiltration applications, non-woven needle-punched fabrics with a characteristic opening size matched to soil grading are specified — typically 90–200 micron.

Related ViaCon solutions

ViaCon supplies geotextiles in all UKCA classes for separation, filtration, drainage and protection. Explore our geotechnical solutions range. Related glossary entries: geogrid, geomembrane, geocomposite and GCL.

Frequently asked questions about geotextile

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