Austral Masonry retaining wall blocks are an ideal choice for retaining walls in gardens, other residential applications and commercial projects. The interlocking and dry stacked nature of these, makes them easy to install for the “Do It Yourself” landscaper. No matter what the project, the result is always an attractive and low maintenance retaining wall. The flexibility of the system provides tremendous scope, from edging to terraces, straight walls to curves.
Note: Please consult with regulating council for local design requirements prior to the commencement of any retaining wall. Councils may request walls over 0.8m in height and / or where a surcharge exists (e.g. driveway, house, fence or other structure) be designed and certified by a suitably qualified consulting engineer.
- String line
- Tape measure
- Walling units
- Compaction tool
- Spirit level
- Agriculture drain pipe
- Pegs or stakes
- Broom Gloves & eye protection
- Mitre saw (to cut blocks if req’d)
- 10-20 mm crushed stone
- Crushed rock (for base)
Step 1: Permits
Check with your local council to ensure all local Building Codes are complied with.
Step 2: Foundation
The foundation material shall be compacted by several passes of a mechanical plate vibrator. Where there are significant variations of foundation material or compaction, soft spots, or where there is ponding of ground water, the material shall be removed, replaced and compacted in layers not exceeding 150 mm. Trenches shall be dewatered and cleaned prior to construction, such that no softened or loosened material remains.
Step 3: Bearing Pad
The facing shall be built on a bearing pad, not less than 150 mm thick and 300 to 600 mm wide, consisting of one of the following options: • Compacted road base • Compacted crushed rock, well-graded and of low plasticity (without clay content), compacted by a plate vibrator; • Cement-stabilized crushed rock, with an additional 5% by mass of cement thoroughly mixed, moistened and compacted by a plate vibrator; or • Lean-mix concrete with a compressive strength of not less than 15 MPa.
Step 4: First Course
Spread 25mm of crusher dust with an additional 5% by mass of cement over the compacted base. The first course is now bedded into the crusher dust. The use of a level and string line is recommended to ensure the first course is laid correctly. Ensure each block is also well filled with free-draining material (eg. crushed rock aggregate / blue metal). For walls up to 1 metre high, make sure at least 100mm of the first-course blocks are buried below the finished ground level. Allow 200 mm for walls over 1 metre high and up to 3 metres high. These walls will need to be engineered.
Step 5: Drainage and Back Fill
Place 100 mm diameter agricultural pipe with geotextile sock behind the wall, with a 1 in 100 fall. Backfill behind the courses of blocks to a width of 300 mm using 10-20 mm free draining material (eg. crushed rock aggregate / blue metal). Ensure each block is also well filled with free-draining material. Backfill behind the drainage layer with selected backfill material in a maximum of 200mm layers. Compaction rate of 95% must be achieved (use only hand operated plate compactors within 1 metre from the back of the wall). Do not use expansive clays to backfill. Be careful not to mechanically compact too close to the wall.
Step 6: Laying Additional Courses
Clean any debris from the top of the wall to ensure the next block sits perfectly. Ensure each block is filled with free draining material, and place next course on top. Place the drainage material behind the blocks to 300 mm. Stack units, placing drainage aggregate and compact backfill for each block layer until the wall is complete. For Heron and Hayman walls it is recommended that you break 20-30% of the back ‘wings’ off to allow backfill material to lock into the block wall.
Step 7: Capping Units
Once backfilling and cleaning is completed as per Step 5 and Step 6 fix the purpose made Capping Blocks with a flexible adhesive. Step 8: Maximum Wall Height This information should be viewed as a guide only. The particular circumstances of retaining wall projects vary significantly in ways that often dictate the use of particular materials and techniques to address challenges presented by those circumstances. Austral Masonry recommends you to ensure that you obtain appropriate professional advice tailored to your circumstances before commencing retaining wall projects.
Step 8: Maximum Wall Height
This information should be viewed as a guide only. The particular circumstances of retaining wall projects vary significantly in ways that often dictate the use of particular materials and techniques to address challenges presented by those circumstances. Austral Masonry recommends you to ensure that you obtain appropriate professional advice tailored to your circumstances before commencing retaining wall projects.