Top Retaining Walls Lower Hutt builds boulder retaining walls in Lower Hutt using large regional rock. A boulder wall is a gravity structure with no fixings and no mortar in it. Every rock gets chosen for its shape, turned until it sits properly, and locked against its neighbours by weight alone.
An operator picks up a rock, offers it to the wall, turns it, sets it down, and often picks it straight back up to try a different face. Each boulder has to bear on three points of contact against the rocks below rather than sitting on soil, because a rock bedded in soil will settle and roll out over a few winters.
That is why boulder walls cost more per metre than block. You are paying for machine time and for an operator who can read a rock before he puts it down.
| Stone | Quarried greywacke, sized to the wall height |
|---|---|
| Placement | 5 tonne digger, each rock set individually |
| Bearing | Three points of contact per rock, never bedded in soil |
| Batter | Leans back, steeper with angular rock than rounded |
| Drainage | Naturally free draining, geotextile behind the face |
| Footprint | Needs depth, so not suited to tight boundaries |
| Best for | Hill banks, bush edge boundaries, larger sections |
Greywacke breaks with flat faces and sharp edges. Those faces bear on each other, so the wall locks up and holds a steeper batter than rounded river rock ever will. On a tight Hutt section where you cannot afford to give up a metre of yard to a leaning wall, that matters more than it sounds.
It also means the wall drains freely through the voids, so water never sits behind the face.
They suit big banks with room behind them, which usually means the hill suburbs. Stokes Valley, Belmont, Kelson, Maungaraki and the bush edge sections out toward Wainuiomata all have banks that a boulder wall handles better than anything manufactured.
They are a poor fit for a tight urban side boundary in Petone or Alicetown. A boulder wall needs a footprint, because it holds ground by mass and leans back as it rises. If you only have 600mm to play with, we will quote you something else.
Every wall we build gets drainage. At least 300mm of clean free draining metal, a perforated coil at the base running to a real outlet, and geotextile over the top so silt cannot block it. It is not an optional line on our quotes.
Same rules as any other wall. Over 1.5m of retained ground, or any surcharge above, means a building consent from Hutt City Council and an engineer. Plenty of hill sections need both because of the slope.
A well built one settles slightly in the first year then stops. The rocks that move are the ones bedded on soil instead of on other rock, which is why placement technique matters more than rock size.
Usually. Send photos with your enquiry. Most of what you will already have on a Hutt section is greywacke, and that is what the local quarries produce.
Our old wall was rotten right through and leaning into the neighbour's place. They pulled the lot out, put proper drainage behind the new one and had it finished in three days. Swept the site clean every afternoon before they left too. Tidiest crew we have ever had here by a long way.
They sorted the consent, which was the bit I was dreading. Dealt with the council so I never had to, and kept me in the loop the whole way through. The driveway sits right above it and has not shifted a millimetre.
Steep section, shocking access, and they still made it look easy. They suggested two smaller walls instead of one big one, which saved us thousands in engineering fees. The terrace in between is now my favourite part of the whole garden.
Call [PHONE] or answer three quick questions. The site visit and the written quote cost you nothing.
