Ag Pipe is an essential drainage product used behind concrete sleeper retaining walls to collect and move excess water away from the wall. By helping reduce water build-up behind the sleepers, ag pipe plays an important role in reducing hydrostatic pressure, improving wall performance, and helping prevent drainage-related retaining wall issues.
Available in 100mm slotted drain coil and 100mm slotted drain coil with socking, this 20m agricultural drainage pipe is suitable for retaining walls, garden drainage, landscape drainage, low-lying areas, and general site drainage where water needs to be redirected to a suitable outlet.
| Option | Size | Best Use |
|---|---|---|
| Slotted Ag Pipe | 100mm diameter x 20m coil | General retaining wall drainage where the pipe will be used with a properly lined drainage zone and clean drainage aggregate. |
| Socked Ag Pipe | 100mm diameter x 20m coil | Recommended where extra filtration is required to help stop fine soil particles entering the pipe slots and causing blockages. |
Ag pipe is installed behind a retaining wall at the base of the drainage zone. Water that moves through the free-draining aggregate behind the wall enters the slotted pipe and is carried away to a legal discharge point. This helps stop water from sitting behind the wall and increasing pressure on the sleepers and steel posts.
For concrete sleeper retaining walls, ag pipe should normally be used with drainage gravel and geotextile fabric. The drainage gravel allows water to move freely down to the pipe, while geotextile fabric helps stop fine soil from migrating into the drainage layer. Without proper drainage, water pressure can build up behind the wall and may contribute to movement, leaning, cracking, or wall failure.
Slotted Ag Pipe has openings that allow water to enter the pipe from the surrounding drainage gravel. It is a practical option for retaining wall drainage where the drainage zone is properly built using clean aggregate and geotextile fabric.
Socked Ag Pipe includes a filter sock around the pipe. The sock provides an added filtration layer to help reduce silt and fine soil entering the pipe through the slots. This is often the better option for retaining walls, clay-heavy sites, silty soils, or drainage systems where long-term blockage resistance is important.
Ag pipe should be installed at the base of the retaining wall drainage zone, behind the sleepers, with the slots positioned to collect water from the surrounding aggregate. The pipe should be laid with a continuous fall toward a suitable outlet so water can drain away by gravity.
A typical retaining wall drainage system includes free-draining aggregate behind the wall, geotextile fabric to separate soil from the drainage layer, and ag pipe at the base of the wall. The pipe should not discharge into an unsuitable area where water can return behind the wall or affect neighbouring property.
For retaining walls in clay soil, silty soil, or areas with poor drainage, socked ag pipe is often preferred because the filter sock helps reduce the risk of fine particles entering and blocking the pipe. Even with socked pipe, the drainage zone should still be built correctly with clean aggregate and geotextile fabric.
Ag Pipe is available in 100mm x 20m slotted and socked options. Delivery is available across Sydney, Melbourne, Brisbane, Perth, Adelaide, Canberra, Gold Coast, and regional Australia. Get a free quote for your drainage materials.
