“Can you build a concrete fence on top of a retaining wall?”
We get asked this question every so often and the answer is ‘if the conditions are right’.
First, it has to be solid concrete retaining wall. Wood tie retaining wall or allan block systems will not work. Next, the precast concrete retaining wall must have sufficient width and a solid foundation for it to sustain the weight of the concrete fence.
Meeting those conditions, a concrete fence can be installed on a retaining wall and there are a three main methods to do so. The methods have limited applications, and it can get quite costly. The three methods are:
1. Bracket Anchor
2. Concrete Drilling
3. Galvanized Steel Post or I-Beam
Let us talk a bit about both methods and the impacts that each have on your wallet and structural integrity of the wall.
This is the cheaper method when compared to concrete drilling. The concept is simple as a bracket or mounting plate is attached to the concrete post and is mounted on the retaining wall.
This method is commonly used in wooden fencing systems that is attached to retaining walls. Due to the weight of a concrete fence, you will require stronger brackets and plates and a larger retaining wall that has a strong foundation to prevent the wall from leaning.
*Choose brackets or plates appropriately depending on height of wall and size of retaining wall
This method is expensive but provides a structurally sound concrete fence. A concrete drilling machine is needed for this method and it takes a long time to drill post holes into concrete retaining walls. Once the holes are drilled, the concrete posts can be casted into the retaining wall to be formed as part of the wall. This is a labour intensive process and requires a large retaining wall in order for it to work.
Galvanized Steel Post or I-Beam
Steel post or I-Beam can be installed on top of the wall via concrete bolts (may require special weld). The pro of this method is that the post/beam is fairly light, thus exert less pressure on the wall. However, custom made posts/I-beams may be required and this could get expensive. Also, for people who love concrete fences, you will not get the "full" concrete look with this method.
There are two alternative methods to installing on a retaining wall and depending on the situation, may or may not apply.
The first method is to install the fence behind the retaining wall and into the ground. This is the simplest solution and most cost effective. However, this method depends on where the property line is and whether there is space for the concrete fence
The second method is to build a retaining wall around the post or have the fencing system installed during the construction of the retaining wall. This method is the best method and should be planned during the planning phase to save potential future headaches.
*With proper pre planning, the concrete post can be casted together with the retaining. The results, a simple, elegant, and uniform wall.