Retaining: What you need to know

Retaining in landscaping can create character and depth to your garden when used for raised garden beds, but as well as that retaining can be a crucially necessary part of the landscape when there are varying levels of the land, either on a sloping property or when there is a height difference between neighbouring properties.

Several construction materials and methods can be implemented to retain soil, and there can be a lot more to it than you may realise.

In Australia, some of the more popular methods for retaining soil, particularly between properties, are with limestone blocks, panel and post retaining, and timber.

As there are so many factors that may influence the best product to use, your best option is to request a free site inspection. Things you may not consider that the experts will, include factors such as accessibility, weight of the product, machinery needed etc. 

Be aware also that there are always the unforseens when any digging or excavating will take place. While all due care may be taken with locating the utilities and reticulation, it is impossible for a trades-person to know prior to digging what else may lie beneath. If you are aware of any tree stumps or difficult roots (palm tree roots can make digging very difficult) that may be in the way but not obviously so until digging commences, it is always advisable to inform your trades-person at the time of the site inspection so they are able to consider additional costs in the quote where possible. If you wait until work commences, everything may come to a stand still while additional costs are calculated, secondary discussions (between neighbours where it is between properties) take place, and additional necessary equipment is chased up. Your fence may end up down longer than was necessary.

Another consideration that comes with the scope of the job where it may be best to consult a trades-person, is knowing whether you will require a structural engineers report to be submitted to your local council for approval prior to the commencement of any work. Different councils may have different rules and restrictions when it comes to height and structural integrity of the retaining.

Above: A fence is being installed between properties with different soil levels. Panel and post retaining was already in place. but still wasn't high enough to meet the height of the higher property. Additional timber retaining was installed to keep the soil from the higher property off the fence, as using a Colorbond fence to hold back soil will make the fence lean and fall over time, and also rust out.

Above: From the other side of the fence (the higher property) once the fence installation was complete, only the top of the timber retaining is visible, as it holds the soil away from the fence. Bevelled limestone blocks retain the soil for the garden bed, to neatly define the garden from the paving.