Block Retaining Walls in Bunbury

What a block wall is

A block wall is built from concrete blocks stacked in courses on a footing, with the hollow cores filled. The national guide calls it besser or core-filled block and says it suits taller structural walls and can be rendered. Ask the builder what block size and core fill they plan, and how the wall is tied into the footing.

What the guide says it costs

The guide, updated by its publisher on 5 June 2026, gives $450 to $800 per square metre of wall face for core-filled block, installed and including GST. That puts it above timber and concrete sleepers on its list. These are national figures, not Bunbury prices, so ask each builder for a written quote with the face area.

Why block suits taller walls

The guide says block is best for taller structural walls and that walls over about 1 metre, sometimes 600 millimetres, usually need an engineer's design and approval. That affects the price before anything is built. Ask whether your wall is likely to need design, who arranges it and whether the fee is in the quote.

Footings first

A block wall starts with a footing, and the guide says harder ground, rock or a surcharge load means deeper and stronger footings. A surcharge is a load above the wall, such as a driveway or a building. Tell the builder what sits above the wall, now or later, and ask what footing depth is quoted and why.

Finishing the face

The guide says block is render-ready. Rendering, paint or capping are separate from the structural work, and may or may not be in a headline rate. Ask whether the quote covers the face finish, the top of the wall and any step or return at each end. Compare quotes only when each includes the same finish.

Drainage still decides

A solid block wall holds water back completely unless it is given a way out. The guide says agricultural pipe, free-draining gravel and weep holes keep water from building up behind a wall and pushing it over. The Bunbury station averages 737.3 millimetres of rain a year. Ask each builder to describe how water leaves.

Heavy-rain days

The Bureau of Meteorology station at Bunbury records an average of 5.2 days a year with 25 millimetres or more, and a highest daily fall of 92.0 millimetres on 4 July 1999. A block wall with poor drainage faces those days under load. Ask the builder what happens to the water when the pipe is full or blocked.

Permit and certificate steps

The City of Bunbury says building work may need a permit. A certified application uses a private building surveyor and a certificate of design compliance, with up to 10 business days for the City to assess it. An uncertified application is assessed by the City, up to 25 business days. Ask which path your builder expects to use.

Near a boundary

The City of Bunbury lists the BA20 form for a request for consent to encroach or adversely affect, and the City of South Perth says a wall may go across a boundary only with written agreement from the neighbours. Block walls are often built right at the edge of a lot. Ask who is responsible for the paperwork and the neighbour.

Registration

The Western Australian Government register page says builder-work valued over $20,000 needs a registered building service contractor, and says to check the name, number and licence type. It does not say whether a wall is covered. Ask the business which registration applies, ask for the number and check it before you sign.

The quote

List length, height, face area, block type, core fill, footing, reinforcement, drainage, finish, waste removal, any design and permit fees and the warranty. The guide says to check whether the price is fixed or an estimate. Ask three builders for the same wall and ask each to explain any large gap.

Next steps

Read the engineered wall and cost guides, then send the form with your suburb, the length and height you need and a photo of the slope. Independent builders who cover Bunbury may reply, and you can ask each one about footings, drainage and approvals. We do not build walls or check businesses.

How much does a block retaining wall cost?

One national guide gives $450 to $800 per square metre of wall face for core-filled block, installed and including GST. Ask for written Bunbury quotes.

Is block better for tall walls?

The guide says block suits taller structural walls, but it says taller walls usually need an engineer and approval. Ask the council and the builder.

Can a block wall be rendered?

The guide calls block render-ready. Ask whether render or paint is in the quote, since it may be priced separately.

Who checks the builder?

You do. The state register page says to check name, registration number and licence type. We do not check anyone.

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