Having built fences in neighborhoods that are just about as hilly as San Francisco, I've encountered many creative ways to build fences that negotiate a hillside. Due to their picket, rail, and post design, metal security fences are one of the more troublesome fence types when it comes to building on a hill. Security fences are so named because they are supposed to keep people and animals both inside and outside the fence. To do this successfully, the fence pickets need to closely follow the contours of the ground.

In my extremely hilly old neighborhood, one particular fence’s failure to follow the contours of the ground consistently became the misfortune of whichever mail carrier had to take the route, as the three dogs in the yard would crawl under the fence in order to chase them. When installing a hillside security fence that will promote the wellbeing of your mail carrier and keep animals and small children safe and secure, it pays to choose a fence designed to easily adjust to a variety of grade changes.

Two Hillside Fencing Strategies

When building a fence on a hill, there are two general approaches. The first is called "stepping," which is exactly how it sounds. Fence posts are placed into the ground, with the horizontal rails arranged like steps running down the slope. This method will very often leave large gaps between the ground and the bottom rail. If you begin observing fences with this problem, you'll see that people improvise all sorts of solutions, from elegant stone retaining walls to not-so-elegant chicken wire.

If having a gap below the fence is a problem, as it may be with a security fence, the second strategy, called "racking," involves closely following the contours of the slope. A rackable fence possesses pickets and rails that are joined flexibly, allowing the rails to be positioned in contour with the ground, and sometimes offering a few options for where to attach the rails onto the fence post.

Optimal Racking Systems

Not all racking fencing systems are created equal. There are a few features that will make installing a rackable security fence easier and more aesthetically pleasing.

Panel Length: The length of the fence panel will determine how many posts need to be used. Metal picket fence panels are generally 6 feet long. However, a longer panel will cut down on the time, extra concrete, and money involved in setting more posts. If you have found a system with longer panels, it is important to consider the strength of the material in the panels, brackets, and posts, as the stresses will be greater.

Welded Internal Hinge: In a rackable fencing system, the point at which the picket is connected to the rail is a place that has to include both the flexibility to adjust to grade changes and the strength to stay in place once the fence is installed. Some fencing systems handle this important joint through screws and bolts. The main weaknesses of this method are that the parts aren’t tamper-proof, that they are exposed to corrosion-producing weathering, and that extra labor time is often involved in order to tighten and loosen the pickets along the rail to suit the grade. Many manufacturers also use a tab welded from the rail to the picket--this tab is bendable, creating adjustability. This method is not ideal as it fatigues the steel and can cause cracking and cracked metal coatings. Another option that doesn’t possess these problems is a welded pin hinge system. This arrangement possesses both strength and flexibility as the adjustability comes from a true hinge system, not merely a bendable piece of metal. Since the moving parts are protected from the weather, this system is more resistant to corrosion than systems that utilize exposed screws and bolts. In addition to the practical benefits, the internal hinge system delivers an aesthetically pleasing, clean and smooth finish to the rails, as there are no screw or bolt heads sticking out.

For a DIYer, or someone like myself who used to be a contractor, putting in a security fence on a hillside can provide ample opportunities for head scratching and frustration. While some of us might elect to fill any gaps under the fence with stone or brick retaining walls, I think the majority of us would rather have a fencing system that does all the work for us. Versai™ ornamental steel fencing from Fortress Building Products combines a cost-saving 8-foot panel length, a patented internal pin hinge system, high-quality galvanized steel, and pre-punched mounting holes. For other construction needs, take a gander at the full range of innovative products from Fortress® .