Concrete sleepers are renowned for their durability, strength, and even aesthetic appeal. They’re also versatile, coming in various shapes, sizes and designs to enhance your outdoor space. From incorporating stylish modern firepits to creating a garden feature, concrete sleepers are hot on the DIY list for handy homeowners.
But how high can concrete sleeper retaining walls go?
The maximum height of a sleeper retaining wall is 2.8 metres. And the higher the wall, the more engineering support is required. This could mean installing additional steel posts for your wall’s reinforcement.
Height of Concrete Sleepers
Concrete sleepers heights for retaining walls vary in height, requiring different widths and lengths for each height and load requirement. Sleeper sizes range between 1.2 metres or 1190mm to 3 metres with the following widths: 80mm, 100mm, 120mm and 150mm.
Your concrete sleeper retaining wall’s height will also depend on the following factors:
Soil conditions – Heavier loads require thicker and longer sleepers as the pressure is greater. You’ll first need to estimate your earth’s magnitude and distribution of loads on the wall.
With a 5 kPa soil pressure, the height of your wall can be built between 800 mm to 7500 mm. Retaining wall heights under 10 kPa, will range from 500 mm to 7000 mm. If you’re not sure on your soil conditions, a structural engineer can perform a soil test and provide a report on its pressure.
Reinforcement – Taller retaining walls require thicker concrete sleepers and additional steel rods. The more sturdy the wall, the better able it will be to bear heavy loads and withstand strong lateral earth pressure.
Concrete sleepers – Some concrete sleepers aren’t built to include steel reinforcements, making them unsuitable for higher walls. Make sure to check the concrete sleeper’s specifications before purchasing. All of our concrete sleepers in Melbourne are reinforced with steel for maximum strength. Considering timber? Read this.
Steel posts – For maximum strength, ensure you get steel posts made from galvanised steel. These offer complete protection against corrosion and will last longer than standard steel posts.
Concrete Sleepers thickness and length for Taller Retaining Walls
A concrete sleeper’s thickness and length are also an important consideration for taller walls. The taller the wall, the more structural reinforcement you’ll need to ensure your wall is safe. Thus, they require thicker sleepers and longer lengths to maintain its stability.
Concrete sleeper heights will be based on its size, reinforcement and strength. Unfortunately, DIY builders will have to hire a structural engineer to calculate the height of the wall accurately. You can then purchase concrete sleepers with the right specifications accordingly.
Steel posts are dug into the ground and used to reinforce the wall’s stability.
Generally speaking, the post hole depth should be equal to the wall’s height. For example, post holes should be dug 2010mm for 2.0m sleepers and 2410mm for 2.4m sleepers. For a one metre concrete sleeper retaining wall, post holes should be 1100mm deep with a hole diameter of 450mm.
Like concrete sleepers, Steel posts vary in length and size and are based on the weight of a steel that’s one metre long. For example, 100UC 14.8 h beam is a steel weight of 14.8kg with a thickness of 100mm. Retaining walls taller than two metres usually require 150mm steel, making them stronger and more durable.
Read about The Difference Between Steel H Beams and I Beams here.
Council Regulations for Retaining Walls
Council regulations will also impact the height of a concrete sleeper retaining wall. These guidelines must be adhered to before construction can begin. As a general rule of thumb, wall heights over a metre in length require a building permit.
Each state and the local council has different regulations so contact your council for more information. Your walls engineering will also need to be approved by the local building authority and a structural engineer. This is because taller walls will require additional safety features to ensure their stability against lateral earth pressure. You may also want to check out this concrete sleepers maintenance guide.
Not sure how much concrete sleeper retainig walls will cost you? Check this out.
Taller concrete sleeper retaining walls require the use of heavier, thicker concrete sleepers and steel posts to withstand earth pressure. And once your structural engineer has calculated the soil’s earth pressure and the wall’s height, you can then purchase the required material accordingly.
At RWS, we provide a wide variety of galvanised steel posts and concrete sleepers to fit any wall size. We also provide design and installation services to create a retaining wall that seamlessly blends into your garden. If you’d like more information, please visit our website or contact us directly today. We look forward to discussing your project with you! Our services are available in Melbourne, Brisbane, Gold Coast, and Sunshine Coast.
Did you like this guide on how tall concrete sleeper retaining walls can be? You might like this guide on How to Weld a Colorbond Fence on Top of a Concrete Sleeper Retaining Wall!