How to Remove a Concrete Block Retaining Wall by Yourself

Removing a concrete block retaining wall yourself is possible for smaller walls, but it requires careful planning, the right equipment, and a solid understanding of the risks involved. Before you swing a sledgehammer, there are some important legal, structural, and safety considerations every NZ homeowner needs to know.

Check If You Need a Building Consent First

In New Zealand, retaining walls are regulated under the NZ Building Code. As a general guide, retaining walls over 1.5 metres in height (or walls retaining a surcharge such as a driveway or structure) typically require a building consent — and that means demolishing them may also require consent or at least notification to your local council.

Schedule 1 of the Building Act 2004 lists certain exemptions for minor building work, but these exemptions have conditions. Always confirm with your local council before starting demolition. You can find general guidance on consent requirements at MBIE Building Performance.

Also check whether the wall is on or near a property boundary, as this can affect your neighbours and may involve resource consent under the Resource Management Act.

Assess the Structural Situation

Before removing any retaining wall, you must understand what it's holding back. A retaining wall is doing a job — it's preventing soil, fill, or a slope from moving. Remove it incorrectly and you risk:

• Soil collapse or slip, especially on sloped sections common in many NZ properties
• Damage to nearby structures, driveways, or fences
• Undermining foundations of your home or a neighbour's property

If the wall is over 1 metre tall, retains a significant slope, or sits near any structure, get a structural engineer or experienced demolition contractor to assess it first. This is not optional — it's about your safety and the safety of those around you.

Tools and Equipment You'll Need

For a smaller concrete block wall (under 1 metre, on flat ground, away from structures), you'll typically need:

• Safety gear: hard hat, safety glasses, steel-capped boots, heavy-duty gloves, and a dust mask (P2 rated)
• Sledgehammer (4–6 kg) or electric demolition hammer/jackhammer (available to hire from Bunnings or Mitre 10)
• Pry bar and bolster chisel
• Wheelbarrow for debris removal
• Skip bin or trailer for disposal — concrete cannot go in your kerbside bin

Hire gear is widely available from Bunnings and Mitre 10.

Step-by-Step: Removing the Wall

1. Prepare the Site

• Mark out an exclusion zone — keep children and pets well away
• Check for any services (water pipes, electrical conduits, drainage) running near or through the wall. Contact your local council or use a cable/pipe locator service before digging or breaking
• Photograph the wall and surrounding area before you start

2. Remove Any Capping or Topping Blocks First

Start from the top of the wall and work downwards — never start at the base. Use a pry bar to lever off capping blocks, then work row by row.

3. Break Up Mortar Joints

If blocks are mortared together, use a bolster chisel and hammer (or demolition hammer) to break the mortar joints. Work carefully and methodically. Avoid large swinging blows that could cause sudden collapse.

4. Remove Blocks Row by Row

Lift blocks clear and stack them away from the work zone. Concrete blocks are heavy — a standard 390 × 190 mm hollow block can weigh 10–15 kg, and solid blocks much more. Use proper lifting technique or get a helper.

5. Deal With the Footing

Most retaining walls have a concrete footing below ground level. This may need to be broken up with a jackhammer and removed. Depending on depth, this can be the hardest part of the job.

6. Manage the Exposed Soil

Once the wall is down, the soil it was retaining needs to be managed immediately. Have a plan — whether that's regrading, installing a new wall, or planting — before you start demolition.

Disposing of Concrete Waste

Concrete rubble is heavy and bulky. Options include:

• Hiring a skip bin (check with your local provider for concrete-specific pricing)
• Taking it to a transfer station — most NZ councils accept clean concrete for a fee
• Some demolition contractors will take clean concrete for recycling

Safety: What You Must Know

WorkSafe NZ is clear that demolition work carries serious risks. Key safety rules:

• Never undercut a wall — always work top-down
• Wear P2 dust mask — concrete dust contains silica, which is a serious lung hazard
• Be aware of wall instability — mortared block walls can shift unpredictably
• If you hit unexpected reinforcing steel (rebar), stop and reassess
• Keep bystanders well clear at all times

When to Call a Professional

Call a licensed demolition contractor if:

• The wall is over 1 metre tall or retains a significant slope
• The wall is near your home's foundations, a boundary, or any structure
• You find unexpected reinforcing, drainage pipes, or services
• The job requires machinery (excavator, bobcat)
• You're unsure about consent requirements

A qualified demolition contractor will assess the structural situation, manage consents, handle disposal, and do the job safely. You can find experienced local demolition contractors on tradedirectory.co.nz.

Sources & Further Reading

• MBIE Building Performance – Building Consent Information
• WorkSafe NZ – Health and Safety in Demolition
• BRANZ – Retaining Walls and Site Stability
• Bunnings – Tool Hire and Equipment
• Standards NZ – NZS 3604 and Related Standards