While most fencing is usually installed into the ground, situations exist when a retaining wall or any existing wall needs a fence installed on top of it. There are several methods to accomplish this and they can be different depending on the type of fence you are using.
Aluminum Fence
There are three different methods of installing an aluminum fence on top of a wall.
1. Core-Drill: We recommend core-drilling over all other methods. It is easily the most stable and strongest way to install a fence on top of a wall. If safety and security are the reason for the fence, this method should strongly be considered. The depth of the hole should be as deep as possible but at least 4 inches. Grout (not concrete) should be used to install posts on top of a wall. A core drill can be rented at your local tool rental store.
2. Post with a Welded Plate : This is the 2nd best method of installing on top of a wall. A square plate with holes at the corners is welded to the bottom of the post to create a stable connection between the post and plate. You would then use concrete/masonry anchors to bolt the post down into the wall.
3. Mechanical Deck Mount: This is the least expensive but also the least stable method of attaching a post on top of a wall. This mounting method is best for applications where safety is not a major concern. You use concrete/masonry anchors to bolt the post down into the wall.
Wrought Iron Fence
There are two different ways to install a wrought iron fence on top of a wall.
1. Core Drill: Once again, this is the recommended and most secure method. Use the core drill to bore out a hole at least a little larger than the diameter of the post. The depth of the hole should be at least 4". Quick drying grout (not standard concrete) should be used when installing posts on top of a wall.
2. Post with Welded Plate attached: This type of post can be purchased from Fence-Depot along with your fence. This method is less labor intensive but not as sturdy. Set the post on a level surface and bolt down with concrete/masonry anchors. Then attach fence sections.
Vinyl Fence
There are three different ways to install a vinyl fence on top of a wall.
1. Core Drill: This is the most sturdy method. You don't drop the entire 4"x4" or 5"x5" post into the wall with this method. You take a 2" steel post and sink it into the wall. Then you attach an accessory called an EZ Bracket to the top and the bottom of the steel post. After this is done, you can slide the vinyl post over top of the steel post with the brackets attached. These brackets are either 4" or 5" wide so the vinyl post will barely slide over.
2. Steel Post with a Welded Plate: Purchase 2" steel posts that already have a square plate welded to the bottom. Bolt down the post with concrete/masonry anchors and repeat the procedure from above with the EZ Brackets.
(Note: The above methods require materials that are not sold by Fence-Depot.com. They would need to be purchased locally)
3. Structural Metal Post Insert: This post insert can be purchased from Fence-Depot because it is provided by the manufacturer of the fence itself. It is a round metal post with a plastic square coating that has a plate welded to the bottom. This post mount comes with a leveling plate in case the wall you are installing on top of is not level. Bolt down the post mount using concrete/masonry anchors. Then slide the vinyl post over the top of the post mount.
This has been a summary of some of the ways fencing can be installed on top of a wall. Over 30 years of experience in the fence installation business has taught us that you almost always have to make adjustments to these methods for each individual application but this should help you get started. Please call us to talk with one of our fence installation professionals for help with installing your fence on top of a wall.
More articles about installing fence:
Wrought Iron Fence Installation Manual
How to Install Aluminum Fence
How To Set Gate Posts
