Atlantis

It creates a continuous void between the waterproofing membrane and the soil sitting on top of it. Water that soaks through the growing medium reaches the void and runs sideways to an outlet or ag line instead of pooling against the membrane. That keeps hydrostatic pressure off the waterproofing and stops the substrate staying permanently saturated.

The fabric is not optional in a normal build-up. It is a filter layer that lets water pass into the cell while holding back the fines from the soil or growing medium above. Without it, silt washes into the void and the drainage path slowly blocks up, which is very hard to fix once the planter or deck is backfilled.

Backfilling is where most membrane damage happens. Sharp aggregate, dropped tools, barrow wheels and the drainage cell itself being dragged into place can all nick or abrade a cured membrane. The extruded protection board goes down over the membrane as a sacrificial layer so the waterproofing survives the rest of the build.

The usual sequence from the structure up is membrane, protection board, drainage cell, filter fabric, then growing medium or fill. The fabric always sits above the cell and below the soil, never underneath the cell. Check the technical data sheet on each product page before you set out, as planter, podium and retaining wall details can vary.

Yes, a vertical drainage layer against the back face of a retaining wall does the same job as a horizontal one under a planter. It gives retained water a clear path down to the ag drain at the base instead of building pressure against the wall. Follow the engineer's detail for the wall in question, since drainage requirements are set by the design, not by the product.

Australian work in this area is generally designed around AS 4654 for external above ground membranes and AS 3740 for internal wet areas, with WaterMark relevant to certain plumbing components. Drainage cell, filter fabric and protection board are not the waterproofing layer themselves. They support the membrane system by managing water and preventing damage, so specify them alongside a membrane rather than as a substitute for one.

The full Atlantis build-up is stocked on this page, so the drainage cell, the Geotech Fabric roll and the extruded protection board can be ordered together in one delivery rather than chased from separate landscape and waterproofing suppliers. Availability shows on each product page and orders ship Australia wide. If you are not sure how many sheets or how much fabric your planter, podium or wall needs, send us the dimensions and we will work it out with you.