Retaining Wall Building Tips

Building a retaining wall to improve the flow, usability and appeal of a garden or section is a project that a confident
DIYer may approach.

Here is a quick guide to building a simple interlocking block retaining wall.

  • Prepare and check council regulations
  • Before you start, check with your local Council to see if building approval or engineering certification is required. In general, walls closer than 1.5m to a building, over 1 metre high or on a steep slope, may require building approval and certification by an engineer.
  • Measure and calculate blocks
  • Work out how many blocks you’ll need by measuring the length and height of your planned retaining wall. Add 5% for breakages and cuts.
  • Dig & prepare the base
  • Lay out where you are going to build the retaining wall by running a string line between two stakes, then dig a shallow trench approximately 180mm deep and 350mm wide. Fill with road base or coarse sand, compacting and levelling as you go.
  • Lay the wall, creating drainage as you go
  • Lay your first row using a rubber mallet top tap blocks into place. Ensure the first row is level with a spirit level.
  • Place drainage material, such as gravel or blue metal, about 150mm wide behind your first row.
  • Fill the cores and openings in the top of the blocks and between each block.
  • For interlocking rows, use a masonry saw to cut a block to finish your first row and/or to start the second row to stagger the joints. 
  • When you have completed two rows, add drainage. Lay slotted agricultural pipe on the gravel behind the blocks. Keep one end of the pipe clear – draining to a clear area or a drain – so that the ground water can escape.
  • Continue laying blocks and drainage material. Make sure you compact backfill for each block height.
  • Apply construction adhesive to the last row of blocks to secure in place. This can be on top of the blocks if you’re using capping blocks – or between the second to last and last rows.
  • For maximum protection the retaining wall can be sealed after installation. Check recommendations from the manufacturer.
  • Sweep with a stiff bristled broom to remove debris from the retaining wall.

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COVID-19 Guidelines August 2021

All Design Centres in Victoria are closed until further notice in line with the Government guidelines. We can still offer non-contact “click and collect” yard pick-ups and virtual colour consultations upon request. 

Locations affected include: 

The Geelong Design Centre is now open in accordance with the VIC Government’s updated guidelines.

As you are all aware these are very difficult times, however we trust you understand our concerns and we in-turn appreciate your ongoing support.