Fence or Retaining Wall First? Getting the Build Order Right

Many Brisbane properties need both a retaining wall and a fence, especially on boundary lines where there is a height difference between neighbouring blocks. One of the most common questions we get is which one should be built first.

The answer is almost always the retaining wall.

Why the Wall Comes First

A retaining wall is a structural element. It manages the soil and establishes the ground levels on either side. Until the wall is in place and the ground is stabilised, you do not have a reliable surface to build a fence on.

If you build the fence first and then excavate for the retaining wall, you risk undermining the fence posts. The ground they are set in may shift, settle, or be removed entirely during the wall construction. You could end up having to re-do the fence, which means paying for it twice.

Building the wall first gives you a stable, level base to work from. The fence posts can then be set at the correct height and depth relative to the finished ground level, and everything lines up properly.

Combined Builds Save Money

When both the retaining wall and fence are being built on the same boundary, doing them as one project makes sense. The crew is already on site, the machinery is there, and the two structures can be designed to work together.

In many cases, the fence posts can be integrated with the retaining wall. For example, steel fence posts can be set into the retaining wall footings or bolted to the wall itself. This saves materials and creates a cleaner finished result than building two separate structures side by side.

Quoting both together also tends to be more cost-effective than two separate jobs, because setup, access, and cleanup only happen once.

What About Existing Fences?

If there is an old fence on the boundary that needs to come down before the retaining wall is built, that is usually handled as part of the wall construction. The old fence is removed, the wall is built, and then the new fence goes up.

If the existing fence is in good condition and is not in the way of the wall construction, it can sometimes be left in place and the wall built alongside it. But this is not always possible, especially if the wall needs to go exactly where the fence currently sits.

Height Considerations

When a retaining wall and fence sit together on a boundary, the combined height matters. Some councils have restrictions on the total height of a retaining wall plus fence, often around 2.4 metres. If the wall is 1 metre and the fence is 1.8 metres, you may be over the limit and require development approval.

Your fencer or engineer should flag this during the quoting process. It is better to know about height restrictions before construction begins than to be forced to modify the design after.

Plan Both Together

If you know you need both a retaining wall and a fence, get them quoted together and plan the build as a single project. The sequencing, design, and cost all work better when the two elements are coordinated from the start.