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What are Anchor Bolts?

A close look at a row of anchor bolts.

You’re pretty handy with a hammer and screwdriver. You’re not afraid to get your hands dirty, to crawl under the sink, to open up that panel, to do it yourself. You can work with plywood and drywall and insulation and piping. But when you see concrete, you just stop. Even the savviest DIYer can be daunted by concrete. But you don’t have to be afraid.

You can drill into concrete and secure objects to it. You just need to have the right bolt. And when it comes to concrete, the right bolt is the anchor bolt. When you know how to work with anchor bolts, concrete won’t ever stop you again. And when it comes to your home and the projects you want to complete, you definitely shouldn’t let anything stop you at all.

Related: All Types of Bolts | Rock Bolts | Shoulder Bolts | Lag Bolts | Arbor Bolts | Carriage Bolts | Hex Bolts | Elevator Bolts | Hanger Bolts 

Anchor Bolt Designs

Most bolts have a single standard design that varies only in size, but never in shape or style. Anchor bolts are different. There are different types of anchor bolts that are designed to do specific jobs, though all anchor bolts are made to connect with concrete.

So if you’re trying to hang something from a concrete wall, insert a supporting rod or otherwise mount something to concrete, then you’re on the right track if you’ve got anchor bolts. Now, you need to make sure you’ve got the right type of anchor bolt for the job you want to do.

The two most common categories of anchor bolts are cast in place and drilled in place. If you’re using a cast in place anchor bolt, you also need to make sure you’ve got some wet concrete. That’s because after you drill the hole and place the bolt, you pour wet concrete around it to literally cast it in place. An anchor bolt that’s drilled in place is drilled directly into hardened concrete. You don’t need to add additional concrete when you’re working with this type of anchor bolt.

Types of Anchor Bolts

A look at various anchor bolts.

Within those two categories of the cast in place and drilled in place, there are multiple designs of anchor bolts. The four main types that are most commonly used are L-shaped, double end rods with plate, swedge, and headed. 

L-shaped anchor bolts are most commonly used to secure light poles, signs, and heavy equipment to concrete foundations. 

Double-end rods with plate anchor bolts, also simply called plate bolts, have a plate washer secured to one end. This washer is meant to be welded to make the bolt even stronger. Either the washer is welded directly to the bolt or it’s welded to a nut that’s been placed in the concrete. Most often, these types of anchor bolts are used to secure columns that support buildings, signs and other structures. 

Swedge anchor bolts are made with a round steel bar that is threaded only at one end. The other end is “swedged.” This means it has little indentations. These dents are meant to be filled up with wet concrete, which will harden around the bolt are create an extremely secure connection. These bolts are typically used in constructing piers and girders. Swedge anchor bolts are usually galvanized for additional durability.

Headed anchor bolts have a head on one end, usually hexagon- or square-shaped. The head is made to be embedded into concrete to support bridge railings, poles, and columns. 

 Because anchor bolts are meant to be drilled into concrete, they are usually longer in size than many other types of bolts. Three inches is a pretty typical length, though anchor bolts come in a big range of length and diameter sizes. When you’re placing bolts in concrete in order to secure something to the concrete, you should bury your bolt at least two inches deep for it to be effective. 

Using Anchor Bolts

A look at anchor bolts in a construction site.

It is possible to put a hole into concrete to place a bolt inside…just as long as you’ve got the right tools. You shouldn’t be working on any super-heavy construction projects around the house, so there really isn’t any need for you to get wet cement and use cast-in bolts.

For most home projects, a drill in place anchor bolt will work. A standard headed design should suit most home projects perfectly. Once you’ve got the right type of anchor bolt, use the right technique to place it in the concrete and move forward with the project you have in mind.

For starters, you need a power drill with a masonry drill bit. This drill bit is meant to take the force of biting into the concrete. Use this to pre-drill a hole and get it to the depth you need for your bolt. If the bolt is three inches long, your hole should be three inches deep. Work slowly but steadily. Take a break if needed to avoid burning out your drill. Making a deep hole into concrete is not an easy project, so take your time with this task. Your patience will pay off.

Use a can of air to clear out all the dust and debris in and around the hole. Place a nut and washer at the end of the bolt. This will make it possible for you to grip the bolt with a wrench. Next, you can insert your anchor bolt into the hole and twist it into place. If you have any trouble getting the bolt all the way into the hole you drilled, use a hammer to tap against the end of it and make sure the bolt is hitting the bottom of the hole. Remove the nut and the washer and you’re ready to move on with your project.

A look at anchor bolts sticking out of the concrete foundation.

Anchors Aweigh

Who says that concrete has to stop you? It is possible to hang shelves, put up cabinets, place nails for hanging pictures — whatever you want to do in and around your home, you can do. When you have the right tools and the right knowledge, anything is possible. So you go right up to that concrete and start making plans.

Use your imagination and think about all those things you want to do. When you’ve got the right bolts, you can make any home improvement project a reality. Anchor bolts are your answer for turning any concrete wall into your personal pegboard. So start hanging, start securing, and start having all kinds of fun. Because let’s face it: when you’re more powerful than concrete, you’re going to have a whole lot of fun.