In New South Wales, building a retaining wall taller than 600mm from ground level requires municipal approval. You might assume that if you require a construction permit, you will also need a structural engineer. However, a simple hand-built wall is considered to be an extension of your property and so does not require a permit.
It is important to remember that retaining walls serve two main purposes: to retain soil and to provide support for structures or buildings. As long as you keep this in mind when designing your wall, you should be able to construct whatever height you desire.
The most common type of retaining wall is the gravity-based wall. These are made out of stacked blocks or poured concrete. The height achievable with a gravity-based wall depends on how many blocks or layers of concrete you use to create it. For example, if you were to use six 300mm × 6mm × 6m blocks to build a wall about 1.5 meters high, it would be considered a moderate size project that would not require a permit. Larger or smaller projects could easily be done without a permit as well. It is important to note that changes may be required depending on what kind of soil you use and where you intend to place it. Soil types can be divided into three general categories: solid, liquid, and powdery.
If the wall is more than one metre high and close to a road or footpath, or more than two metres high elsewhere, planning approval is necessary. Independent, freestanding retaining walls may not need to be approved by building officials. Any construction, however, must be structurally solid and carefully maintained. Natural materials such as stone and soil tend to be stable over time.
Retaining walls can be used for a variety of purposes including protecting buildings, creating garden features like terraces or ponds, or providing support for other structures like fences or bridges. The type of wall used will determine how it can be used effectively. For example, a concrete wall would not be suitable for creating a pond because it would be difficult to fill with water. A stone wall could be used for this purpose since it would allow water to drain through and hold its shape well.
It is important to consider how the wall will be used before it is built. This will help ensure that it is constructed properly and remains safe for use even after years of exposure to weather and traffic on nearby roads.
A retaining wall can be an effective way to protect property values by preventing erosion and flooding. It can also create a desirable landscape feature that may encourage people to visit and enjoy your yard. However, no matter what purpose you plan to use it for, ensuring that the wall is safe for use and meets local requirements is essential.
A structural engineer's report is not required to erect a 1 m high retaining wall. It just requires the use of rebar in hollow concrete blocks that tie through to the footings and are filled with concrete. The blocks should be set back from the property line at least 2.5 m to allow for water runoff. The wall needs to be at least 3 cm in thickness if made of compacted gravel or soil.
In most cases, homeowners can erect a retaining wall on their own without using a professional. However, they should always check with a licensed contractor before starting work.
Because of soil erosion, your retaining wall should be built on a sturdy gravel foundation. Choose gravel with stones ranging in size from 1/2 inch to 3/4 inch. Add a 2- to 3-inch layer of gravel to the trench. Then add a 4- to 6-inch layer of gravel on top. The purpose of this base is to provide stability for the wall and prevent it from being washed away by water.
You can use any number of different materials to create a retaining wall. Some popular options are: rock, dirt, concrete, and metal. Each option has its advantages and disadvantages. For example, a concrete wall is very durable and won't deteriorate over time. It's also heavy which may not be an issue for some people. A metal wall requires no additional landscaping and looks great when painted red or black, but it's also very expensive. A rock wall needs to be maintained regularly and requires more work to create than other options. But it's cheap and long-lasting.
The type of material you select depends on how much money you want to spend and what your lifestyle is like after the wall is done. If you plan to live somewhere where there is limited access to water, then a concrete or metal wall might not be the best choice because they will need to be maintained frequently and replaced sometimes. A rock wall is the easiest option if maintenance is not an issue for you.