Sloped section? Auckland clay moves, holds water and pushes hard against a wall. We build timber and block retaining walls with the drainage and footings to hold it back for good.
Nearly every failed retaining wall we're called to replace failed for the same reason: no drainage behind it. Water builds up in the clay, the pressure doubles, and the wall leans or bursts. Every wall we build gets drainage metal, geotextile cloth and a drain coil behind it as standard — not as an optional extra.
Walls up to 1.5 metres that don't carry extra load (like a driveway above) generally don't need building consent. Anything higher or load-bearing needs engineering and consent — we'll tell you straight at the site visit and manage that process if it's needed.