Installation Guides

Auger Holes & Pour Concrete #

Now is the time to dig the pier holes for the steel posts.

The standard recommended pier hole width is 450mm and the depth of the hole is the same as the height of the wall eg. 1m high wall = 1m deep hole = 2m length steel post, however please refer to any engineering requirements that are provided as the hole width and post hole depth might need to be different due to a range of factors.

Retaining walls require a lean back for structural integrity, which is usually recommended to be at least 50mm per 1m of height.

To ensure the steel posts remain in the angle required whilst the concrete sets, we recommend the following:

1. Pouring a small quantity of concrete into the base of the pier hole and letting it set so the ground is solid prior to installing the steel posts. This helps avoid the steel posts sinking into the ground whilst the concrete sets.
2. Build a prop to use to hold the steel post in the angle you require them to be in whilst the concrete sets.
3. To get the perfect spacing between the steel posts, use a pre-cut timber sleeper at the exact length the spacing is required for the wall and place it down at the base of the steel post to use as a marker for the other end of the sleeper to place the next steel post along the retaining wall line.
4. The concrete will usually require a few days to set before curing enough to be ready for the installation of the concrete sleepers (refer to the specific concrete supplier information regarding curing times).

Measure the lengths of the steel posts prior to them setting in the concrete to ensure they are the exact height the wall is required to be.

NOTE: Concrete strength #

We recommend that you use at least 25Mpa strength concrete.

When managing a 90 or 45 degree corner you can use pre-welded 90 and/or 45 degree corner posts or utilise two C posts to create these angles. For any other angles required you can utilise the gap between the flange of the steel posts and the sleeper (roughly 10mm) to create angles of up to 20 degrees, or again you can use two C posts to achieve whatever angle you would like.

For a cleaner finish, when dealing with a wall with various heights (seen in the diagram below) you can install two C posts back to back which cater for the wall height it is facing.