Retaining Wall Blocks: A Comprehensive Guide
Retaining wall blocks are one of the most versatile building materials for earth retention in Australia. From simple garden edging to engineered structural walls, block systems come in a wide range of sizes, shapes, and finishes. This guide covers the major types of retaining wall blocks, their costs, and the situations where each type performs best.
Types of Retaining Wall Blocks
Interlocking Blocks
Interlocking retaining wall blocks feature a lip or pin system on the back that locks each course to the one below. This mechanical connection provides stability without mortar for walls typically up to one metre in height. Popular brands in Australia include Adbri Masonry, Baines Masonry, and Austral Masonry. Interlocking blocks are a favourite for DIY-friendly garden walls, though taller walls still require professional installation and engineering.
Besser Blocks (Concrete Masonry Units)
Besser blocks are hollow concrete masonry units that can be reinforced with steel and filled with concrete grout to create extremely strong walls. When fully grouted and engineered, besser block walls handle heavy loads and are commonly used for structural retaining in commercial and residential projects. They are typically rendered or painted for a finished look.
Split-Face Blocks
Split-face blocks have a rough, textured front surface created by splitting the block during manufacturing. This gives the wall a natural stone appearance at a fraction of the cost. They are popular for feature walls and boundaries where aesthetics matter. Explore all concrete block retaining wall options on our dedicated page.
Costs of Retaining Wall Blocks
Block retaining wall costs vary by type and wall height:
- Interlocking blocks: $300 to $550 per lineal metre installed for walls up to one metre
- Besser blocks (rendered): $400 to $700 per lineal metre installed
- Split-face blocks: $350 to $600 per lineal metre installed
These estimates include materials, labour, footings, drainage, and a standard finish. Site access, soil conditions, and wall height all affect final pricing. Read our full block wall cost guide for a detailed breakdown.
Advantages of Block Retaining Walls
- Versatility: Blocks suit curved walls, stepped walls, and tiered designs.
- Strength: Reinforced block walls rival poured concrete for structural capacity.
- Aesthetics: Available in many colours, textures, and profiles.
- Availability: Concrete blocks are stocked at most building supply yards across Melbourne.
Drainage and Engineering
Like all retaining walls, block walls need proper drainage to prevent hydrostatic pressure buildup. A layer of gravel and an agricultural drain pipe behind the wall are essential. For walls over one metre in Victoria, you will need a building permit, engineering design, and a VBA-registered builder to carry out the work.
Choosing the Right Block System
Consider the following when selecting a block type:
- Wall height: Interlocking blocks suit low walls; besser blocks handle taller, load-bearing structures.
- Finish: Split-face for a textured look, rendered besser for a smooth modern finish, or interlocking for a segmental appearance.
- Budget: Interlocking blocks are generally the most affordable option for low walls.
Estimate Your Project Cost
Use our free tool to get a ballpark figure before requesting quotes. Try the retaining wall cost calculator to estimate costs based on your wall dimensions and material choice. We connect you with licensed builders who can then provide accurate, obligation-free quotes for your block retaining wall project.
Ready to Start Your Retaining Wall Project?
Connect with licensed, insured retaining wall builders in Melbourne. Get up to 3 free, no-obligation quotes.
Find Licensed Builders