Retaining Wall DIY
When it comes to your Retaining Wall DIY project, Garden Supplies exclusively offers engineered concrete sleepers in an extensive variety of lengths, thicknesses, colors, and patterns sourced from reputable Melbourne manufacturers.
Irrespective of the scale of your project, we can provide the necessary steel size/length and sleeper length/thickness tailored to your specific design or engineered plans. Choose between 40MPa or 50MPa concrete strength, ensuring the optimal durability for your project’s requirements. Trust Garden Supplies to fulfill all your needs for a successful and robust retaining wall DIY endeavor.
How To Build A Concrete Sleepers Retaining Wall At 1m High
Images supplied by Artisan Building and Construction
Step 1: Check Local Regulations
Before you start, ensure you check local regulations. Depending on your wall’s height, material, location, and design, you may need a building permit. Contact your local council to verify the regulations in your area. Any sleeper retaining wall over 1 meter will likely require a building permit, and you may need a structural engineer to approve the design.
Step 2: Inspect Your Area
Thoroughly inspect the area where you plan to build. Pay attention to the slope and remove any plants or rocks that might interfere. Measure the area to ensure your wall will fit properly. Know the size and length of your steel posts, calculating how deep they need to be installed. Generally, steel post depth should equal the wall’s height plus 100mm for cover on steel.
Step 3: Gather Your Equipment
Ensure you have all necessary supplies delivered close to the wall for easy handling. You’ll need:
- 1.8 tonne excavator
- 450mm auger
- 450mm wide holes
- 1100mm deep holes
Step 4: Time to Dig
Using your equipment, dig post holes with a 450mm diameter, at a depth equal to your retaining wall’s height. Ensure holes are equally spaced to keep the wall level and structurally sound.
Step 5: Setting Supports and Installing Steel Posts
Set up supports and use a string line to ensure the wall is straight and at the correct height. Insert your steel posts into the holes, ensuring they’re level and straight. Pour your concrete into the holes, about .2 m per hole. Allow a minimum of 24 hours for the concrete to set.
Step 6: Placing Sleepers
You can hire or purchase a sleeper grab that has an opening width of 140mm and a safe working load of 350kg. After the concrete has set, place your sleepers between the steel posts. Ensure there is an allowance of 7mm-10mm between the sleeper and the post.
Step 7: Installing Plastic Membrane and Ag Pipe
Roll out the plastic membrane for easier installation. The membrane should cover the back of the wall, providing a protective barrier. Lay the ag pipe on a slope of at least 10mm fall per meter. Use a 100mm socked ag pipe.
Step 8: Backfilling
Option to use either 7mm or 20mm scoria for backfilling. Fill scoria 300mm back from the wall. Allow for soil to cover the folded plastic membrane over the scoria. Install at least 12 inches of granular backfill directly behind the wall for proper drainage. The rest of the area can be filled with native soil.
Installation Photos (step-by-step)
The featured retaining wall is constructed as a non-permit structure, designed to be just under 1 meter in height.
Have supplies delivered close to wall if possible for easy handling.
1.8 tonne excavator.
450mm auger.
450mm wide.
1100mm deep.
Setting supports and using string line to ensure a straight wall and at the correct height.
Filling holes with 25MPa concrete approx .2 m per hole.
Allow a minimum of 24hrs for concrete to set.
You can hire or purchase a sleeper grab that has an
opening width 140mm and
safe working load 350kg.
Concrete sleepers fitted in channels.
After installing the first row to ensure a level foundation, confirm that the top sleepers are also level.
Roll out the plastic membrane for easier installation, 50m rolls can be purchased.
Plastic membrane installed with overhang.
The plastic membrane covers back of wall, providing a protective barrier.
Ag pipe laid on a slope of at least 10mm fall per meter.
Aggie pipe 100mm socked.
Option to use either 7mm or 20mm scoria for backfilling.
Fill scoria 300mm back from wall.
Allow for soil to cover folded plastic membrane over scoria.
Another happy customer!
What local regulations should I check before building a retaining wall?
When it comes to retaining wall work around the home, sometimes it can be difficult to know when you can do-it-yourself and when you need to call in a professional concrete retaining wall installer.
A building permit in Victoria is required for all retaining walls that are:
- constructed on or near site boundaries where there is a risk of damage to the adjoining property, and/or
- 1m or more in height.
A structural engineer will also be required to determine the correct hole depths, steel thickness/length and sleeper thickness/length. See retaining wall engineering table for maximum heights based on concrete sleeper selection.
However, these rules can vary significantly depending on where you live. Australian states and territories have different regulations for building retaining walls. For instance, the height, material, location, and design of your wall can all influence whether you need a building permit. It’s crucial to contact your local council to double-check the specific regulations in your area.
If your retaining wall exceeds 1 meter in height, it’s almost a certainty that you’ll require a building permit. Additionally, a structural engineer must approve the wall’s design and stability to ensure it meets safety standards.
40MPa Concrete Sleepers – Height Capacity
Lastly, if your retaining wall is being built on a property line, both you and your neighbor will have to share the costs of construction. Make sure to inform your neighbor as early as possible to sort out any disputes and agree on the shared responsibilities.
*Garden Supplies cannot be held liable for any retaining walls built incorrectly due to the wrong materials ordered. We can offer advice but the responsibility lies with you as the customer to have followed council guidelines and engineering.
How do I measure and prepare my area for building a retaining wall?
Consider factors such as:
Soil type, slope, and intended function.
Hole depths should be determined prior to purchase retaining wall steel posts.
Property access for delivery of materials and machinery is required.
Inspect Your Area
Before you commence digging, you’ll need to thoroughly inspect your retaining wall area. Pay special attention to the slope of your garden, and remove any plants or rocks that might interfere with your wall’s construction.
Next, measure your area to ensure your built wall isn’t too big or small. You should know where your wall will start and end.
You should also know the size and length of your steel posts, calculating how deep they need to be installed. Generally speaking, steel post depth should equal the wall’s height plus 100mm for cover on steel. So if your wall is 3.0 metres high, then your steel posts should be 3.1 metres deep.
Now, you’re ready to start digging!
What is the recommended diameter and depth for post holes when building a retaining wall?
Hole depths should be determined prior to purchase retaining wall steel posts. Post holes should be dug with a 450mm diameter, at a depth equal to your retaining wall’s height. Ensure your holes are equally spaced, as this will keep your sleeper retaining wall level and structurally sound. Unequal spacing can result in a noticeable tilt in your wall.
Always remember that hole diameter and size depend on the size of your steel posts.
How do I manage drainage and backfilling for a retaining wall?
Proper drainage and backfilling are critical to the stability and longevity of your retaining wall. Here’s a detailed guide to ensure you’re doing it right:
Drainage System
Hydrostatic Pressure Management: Water pressure can be as damaging as soil pressure. If you have a nearby water source, hydrostatic pressure can build up and potentially cause your retaining wall to collapse if not installed correctly.
Ag Pipe Installation:
- Slope: Ensure your ag pipe is laid on a slope of at least 10mm fall per meter. This helps in effective water drainage away from the wall.
- Pipe Type: Use a 100mm socked aggie pipe.
Drainage Material:
- Bed Material: Place the pipe on a bed of clean drainage material, such as 10-20mm gravel.
- Scoria Options: You have the option to use either 7mm or 20mm scoria for backfilling.
Backfilling Process
Placement: Fill scoria 300mm back from the wall. Make sure to install a minimum of 12 inches of granular backfill directly behind your retaining wall. This ensures proper drainage and supports the wall structure.
- Granular Backfill: The first 12 inches immediately behind the wall should be filled with granular material like crushed stone for optimal drainage.
- Native Soil: The rest of the area can be filled with native soil, which was removed during the initial excavation.
Membrane Installation:
Cover: Allow for soil to cover the folded plastic membrane over the scoria. This helps to prevent soil from clogging the drainage material and ensures water can flow freely.
Final Steps
Backfilling your wall should be the final step after ensuring all drainage components are properly installed. Remember, the primary purpose of a retaining wall is to counteract soil pressure. Without proper backfilling, your retaining wall is as good as a freestanding structure, which could lead to failure.
By following these steps, you can effectively manage both soil and water pressures, ensuring the durability and effectiveness of your retaining wall.
Walls Under 1 m High
Small retaining walls and concrete sleeper garden edging that do not exceed 1m or more in height do not require a permit.
Have more questions ?
Click on the link for more FAQ’s about concrete sleepers & retaining walls
https://garden-supplies.com.au/retaining-wall-faq/
Garden Supplies provides on-site estimates for those who opt not to undertake the DIY approach.
Upon accepting the provided quote, the recommended retaining wall installers will proceed with the project. Following the completion, Garden Supplies conducts a follow-up to ensure customer satisfaction.
The endorsed concrete retaining wall installers boast years of experience and adhere strictly to quality standards. They do not compromise on the construction process for cost reasons. It’s a commitment to building it right or not at all, regardless of lower quotes from competitors.
