I was going to pick up a couch from my friend's father-in-law, and when I arrived at the house, I was shocked to pull up to the black gate of Mordor. His father-in-law's house is built on a hill, and has a seven-foot-high retaining wall in the front yard. Below the wall is a large koi pond. Normally, behind this is an area made out of pavers, with patio furniture and a cloth-covered pavilion. When I visited, though, this seating area had been replaced with piles of dirt and a series of four-inch-wide steel tubes driven into the dirt behind the wall. They were crooked, and the overall aesthetic was that of an evil overlord from a fantasy novel.
When my friend's mother-in-law answered the door, I asked her if they'd beaten the medieval army. Laughing, she replied that her husband was putting up a railing to keep the grandkids from tumbling into the pond, and that they were still working it out. It dawned on me then that the average DIYer is not always familiar with how to install railings in concrete, and that I might be able to help.
Concrete Fasteners Past and Present
Good fasteners that would allow you to attach something to concrete weren't available for a long time, and one of the reasons for my friend's father-in-law's improvisation was that he hasn't worked with his hands for decades. In the early part of the twentieth century, you would use masonry nails to anchor wood to the concrete, and then you'd anchor things to the wood. Alternatively, you could drill a hole into the concrete, stuff a wooden plug into the hole, and drive a screw into the wood, relying on the friction between the wood and the concrete to hold the screw-and whatever it was holding-in place. These wooden plugs were later replaced with plastic, and this technique is still used to hang pictures on walls.
Neither of these methods of anchoring to concrete is really strong enough to hold a railing that people lean on, which is why old brownstone iron railings were usually buried in the concrete. People would chisel out holes in the concrete for the railing posts, plant the posts into the holes, and then pour concrete patch into them. So the wall of stakes I saw at my friend's father-in-law's home was just his way of trying to secure the railing without having to use a chisel.
Fortunately for those of living in the modern era, there is a fastener that can be used in concrete that also holds strongly enough to be used to secure railings. It's called a wedge anchor, and they've been around for awhile, with a version being patented in 1898. It didn't seem to catch on right away, though, with Popular Mechanics treating them like a new development in 1935. For whatever reason, they don't seem to have come into normal everyday use until sometime after the 1960s.
In their modern form, wedge anchors are simply bolts that are wider at their tips, with a clip that surrounds the bolt higher up on the shaft. These are inserted into a hole drilled in the concrete, the bolt is tightened, and the clip slides over the wider part of the shaft-the wedge-effectively expanding the diameter of the bolt and wedging it into place.
How to Install Railings in Concrete Using Wedge Anchors
To install railings in concrete, a wedge anchor about ⅜ inch in diameter and three inches long is the approximate standard. Before you start, you'll first need to drill holes for the anchors. To mark where you're going to drill, it's helpful to measure out your post spacing, place the posts, and mark through the holes that are already drilled in the post base. This will prevent misalignment of the drilled holes when it's time to install the posts.
To drill the holes, use a masonry bit that is the same diameter of the shaft of the anchor. For a typical ⅜-inch anchor, for example, use a ⅜-inch bit. Drilling the holes will be easier with a hammer drill, but it isn't a requirement. If you're using a regular drill, go slowly to avoid burning out the motor. When drilling the holes you will want to go a little deeper than the length of the anchor. While there is no hard and fast rule, I like to drill a half inch deeper than the length of the anchor I'm working with. This prevents the anchor from hitting bottom, and the extra space will give the dust a place to settle below the anchor. You still need to blow the dust out of the holes, but not all of it can be removed and giving it a place to go below the anchor will make life easier.
Once all this is done, put your posts into place. Then take the wedge anchor and put it through the hole in the past base and into the hole in the concrete beneath. It should be a fairly tight fit, and you may need to gently tap some of the wedge anchors into place with a hammer. When the end nut is flush with the post base, turn the nut with a hand tool. This will pull the thick part of the shaft up into the sleeve and wedge the anchor into place. Overtightening can break the anchor, and when they're broken it's a pain to remove the shaft, so no power tools, and when it's done, it's done.
Choosing a Railing System for Concrete
Installing railings in concrete is going to be the same for most types of railings: putting a wedge anchor through a post base. With wooden posts you have to place the post in a metal post base and then anchor that. In metal railings, the post base is just a plate with holes in it that's welded to the post. While it's possible to do this welding yourself, it requires special skills, and it's best, you're a DIYer, to choose a metal railing that's easy to install, such as a system with preassembled panels. It's also best to choose a railing system that will hold up for a long period of time without rusting or breaking down. Concrete wedge anchors are designed to be permanent, and if you need to replace a post that's been attached to concrete using a wedge anchor, this can be difficult to do.
Fortress Railing provides steel railing systems that are perfect for use with wedge anchors. The sturdy steel post bases are welded to the posts and the galvanized steel is given a zinc pre-coat, an e-coating and a high-quality powder coat, which keeps the post and welds from corroding. Fortress Railing also makes lines of aluminum, cable, and glass railing systems that will match different home styles from the rustic to the contemporary, and are easy to install. To find out more, contact Fortress or find a seller near you. For more high-quality outdoor products, take a look at Fortress' lines of decking and fencing.
Image courtesy of Zeizmic at English Wikipedia [GFDL (http://www.gnu.org/copyleft/fdl.html) via Wikimedia Commons