Geotextile Fabric for Retaining Walls

Geotextile Fabric for Retaining Walls — Wall Liners & Soil Separation

Geotextile fabric — also called wall liner or filter fabric — is installed behind a concrete sleeper retaining wall to separate the drainage aggregate from the retained soil. Without it, fine soil particles migrate into the gravel drainage layer over time, blocking ag pipe and weep holes and causing the drainage system to fail. In reactive clay soils, this failure can happen within a few years of construction.

How Geotextile Fabric Works

Geotextile fabric acts as a permeable filter: water passes through freely while soil particles are held back. It is installed against the retained soil face before backfilling with drainage aggregate, creating a long-term separation layer that keeps the drainage system functioning for the life of the wall.

Installation Guidelines

• Line the entire retained soil face from the base of the wall to the top of the drainage aggregate layer
• Overlap joins by a minimum of 300mm to prevent soil migration at seams
• Use in conjunction with ag pipe drainage and weep holes for a complete drainage system
• In reactive clay soils, geotextile fabric is not optional — it is essential for long-term drainage performance

Read our Geotextile Fabric Guide and Complete Drainage Guide for full installation detail. See our full Drainage Kits range for everything needed.