Plan subsoil drainage behind retaining works or around landscape areas where a designed solution is needed.
Soggy lawns, wet retaining walls and damp slabs often point to hidden water, and Sutherland Shire AG Pipe Drainage Installation removes it from the ground. We install slotted pipe in gravel with correct falls and outlets.
Tell us where the problem occurs and what is nearby, such as walls, paths or buildings. Proper placement, filter cover and discharge points help the system work without clogging or causing issues elsewhere.
Across Engadine, Menai, Jannali, Caringbah and Cronulla, sloping sites and retaining walls commonly need subsoil drainage. Careful installation protects your structures and keeps your yard drier and more usable.
Explore the scope ↓We install slotted agricultural pipe surrounded by clean gravel, behind retaining walls, along footings or across wet, boggy lawns, allowing groundwater to enter the system and drain away, relieving pressure behind walls and under slabs, saving you damp problems later.
Filter fabric wrapped around the gravel prevents soil from entering the pipe, helping your drainage system work effectively for years without blockages, maintenance headaches or repeated excavation, saving you future repair costs and stress. Inspection points can also be added.
Each line is laid with consistent falls and connected to a suitable outlet, such as a stormwater pit, soakwell or approved kerb outlet, ensuring collected water leaves your property without causing issues elsewhere, protecting your property and your neighbours' land.
The pipe sits on a firm base set to a continuous fall. It usually sits near footing level, collecting water before pressure can build up behind the wall. A soft or uneven base lets the pipe sag and trap water.
Perforated pipe collects water that reaches the wall. Slots generally face down, and the pipe is often wrapped in a filter sock. Use the pipe type the wall design specifies, and reject crushed or kinked lengths that slow the flow.
Clean, washed aggregate around and above the pipe gives water a fast path. Soil mixed into it blocks the voids. Dusty or unwashed material can do the same. The gravel usually runs up behind the wall, capped below the topsoil.
A fabric layer keeps fine soil out of the gravel. Without it the drain clogs gradually over a few years. Lap the joins, avoid tearing it on rock, and wrap it fully over the top of the stone before backfilling.
The pipe must discharge somewhere approved, such as a stormwater pit or a point at the wall end. A drain with no outlet is a pond behind the wall. Keep the outlet visible and clear of mulch, soil and grass.
A flushing riser at the high end lets the drain be checked and cleared later. Without one, a blocked pipe means digging behind the wall. Bring it up to the surface with a screw cap and note its position for future owners.
Decide where the pipe exits first, then set a consistent fall back along the wall base. The outlet level controls how deep the drain sits at the far end, so check it works on long walls before any building starts.
Excavate to the specified width and depth behind the wall footing, and trim the bottom to line. Compact it so the pipe will not sag. Sandy or wet ground can slump into the trench, so keep the open cut stable.
Place geotextile so it can wrap over the top of the gravel later. Leave enough fabric on both sides to overlap well, and keep it against the trench sides so it does not bunch or tear when stone goes in.
Lay the pipe on a bed of aggregate and cover to the specified depth. Check the slots face as the design shows, join lengths with fittings, and run the pipe to the outlet without kinks. Keep soil off the stone.
Pour water in at the high end and watch it come out the outlet before backfilling above. Slow or no flow points to a sag, blockage or crushed section, and fixing it now beats digging out behind a finished wall.
Installed the wrong way, the pipe can fill with silt and hold standing water at the bottom. It is easy to miss, because the drain looks finished once covered in gravel. Ask which way the slots face on your design.
Backfilling by tipping soil straight on the aggregate buries the filter. Fabric should be wrapped over the stone first. Machines tracking over open gravel, or muddy runoff washing in during a storm mid-job, can contaminate the stone just as quickly.
A flat pipe or one that ends against the wall just stores water. With nowhere to go, saturated soil behind it adds pressure the wall was not designed to carry. The drain needs a continuous fall to a clear outlet.
Ag pipe is for groundwater, not stormwater from downpipes. Piping roof water into it overloads the drain. Water then forces out through the slots into the soil behind the wall, saturating it further. Roof water belongs in sealed stormwater pipe.
Wet lawns, damp slabs and failing retaining walls often point to hidden groundwater, and our AG pipe experts know how to remove it. We install slotted pipe in clean gravel with filter fabric, consistent falls and a suitable outlet, so water drains away without blocking or causing problems elsewhere. Clear communication helps you understand where the problem is and how we will fix it. With local knowledge of Sutherland Shire sloping sites, clay soils and retaining walls, we deliver reliable subsoil drainage that protects your home and structures, keeps your whole yard drier and saves you from costly repeated repairs.
Talk to our team ↗ Same pipe, different job. Work out which one you need before digging.
Groundwater conditions, filter material and outlet position.
Ask us about your project ↗Almost always yes. Whatever the wall type, drainage behind it is critical, and the wall design or engineer will specify it. Do not leave it out to save cost.
Typically yes, via a pit or an approved connection. A licensed plumber should do the connection, and it must not go to the sewer.
It can last for decades if the fabric is intact and the outlet stays clear. Poor installation is the usual reason it fails early.
Sometimes, by digging down the back of the wall, though it can be difficult and may affect the wall. An engineer should check first.
Share the address, the access and the result you need.
Details first. Then a plan that suits the site.