Auckland Retaining Wall Drainage Systems

We spend a lot of time looking at walls that have started to lean, and water is behind nearly all of them. That gives us a fairly practical view of what works — and it's rarely the wall material that's at fault, it's what was or wasn't put in behind it.

Auckland clay is the reason this matters here more than most places. Clay holds water and swells, so pressure that would drain away on a sandy site instead sits against your wall through every wet month. We design the drainage around that, not around a generic detail.

We also handle existing walls, not just new ones. If your wall is bulging, cracking, or weeping water through the face, we can usually retrofit drainage and relieve the pressure rather than you having to rebuild the whole thing.

We use clean drainage metal, not whatever fill happens to be on site. Aggregate with fines in it clogs, and once the void space is gone the drainage layer is just expensive dirt. It's a small material saving that costs you the wall.

We always wrap the aggregate in filter fabric. Without it, soil migrates into the drainage layer from the fill side and slowly chokes it, which is why plenty of walls drain beautifully for three years and then stop.

And we think about where the water ends up. A drainage system that dumps water at the base of your slope, into a neighbour's yard, or against your foundations has just moved the problem. We connect outlets to a proper stormwater or land drainage route.