I Have a Secret: I Enjoy Fastening Things to Concrete
Did you know that fastening things to concrete can be strangely addictive? It’s a confession I have to make. This unusual habit started back in my college days, and I’ve been at it for 35 years now. Concrete anchors come in various types, but I’ve always preferred the heavy-duty ones. Plastic anchors never interested me; I went straight for the big guns. From 1/2-inch lead shields to sleeve anchors and even wedge anchors (or as some know them, Redheads), I’ve tried them all. It’s a habit I’m not proud of, but I just can’t seem to break it. It’s just too much fun, as long as you do it right.
Using Concrete Anchors: The Right Way and the Wrong Way
However, I must warn you that using concrete anchors the wrong way can be incredibly frustrating. It might even lead you to unleash a stream of profanity while contemplating the dunking of your power tools in the nearest lake. Each anchor has its own unique installation method and quirks. This can be confusing if you’re not sure which anchor to use in a particular situation. But fear not, my friend, for this article will clear up any confusion and help you make the right choices.
Table of Contents
- Types of Concrete Anchors
- Tools for Concrete Anchor Bolt Installation
- Summary of Concrete Anchor Bolt Types and Usage Methods
On any construction site, you’ll find a wide array of concrete anchors. As an experienced user, I rely on several types regularly. However, it’s worth noting that the strongest anchoring systems use resin-based anchors, which are commonly found in industrial and commercial settings. These anchors are typically expensive and specialized, making them less suitable for everyday use unless specified by professionals.
If you’re looking for anchors that offer precise torque control, there are options with bolt heads that snap off at a predetermined torque level. These anchors are quite pricey and should be reserved for projects that require extremely tight tolerances and absolute safety. Think long-span bridges or nuclear power plants.
Now, for those of us who don’t have the luxury of spending $600 on a toilet seat, there’s a type of concrete anchor that’s commonly used: wedge and sleeve anchors. These anchors are excellent choices when it comes to holding substantial weight and providing strength against pull-out and shear forces. However, be cautious when installing them near the edge of concrete, as they exert a significant shot/wedging force that can potentially damage the concrete.
Examples of common types of concrete anchors, including wedge anchors, sleeve anchors, large diameter concrete anchors, lead shields, plastic anchors, and Tapcons (concrete screws)
Wedge and Sleeve Anchors: Powerful and Reliable
Among the various concrete anchors available, wedge and sleeve anchors are two of the best options. They provide remarkable strength against pull-out and shear forces. However, it’s important to avoid installing them within 3 inches of the concrete edge, as the shot/wedging force they exert can cause damage. As someone who has used both types extensively, I can confidently say that wedge anchors are my personal favorite. They offer exceptional strength and reliability.
Wedge anchors (AKA Red Heads which is a brand name)
Sleeve anchors with the correct size holes to list on the anchor
How to Install Wedge and Sleeve Concrete Anchors – Drilling
When it comes to installing wedge and sleeve anchors, the procedure is the same. First, use a hammer or rotary hammer drill to create the appropriate size hole. Then, insert the anchor and gently tap it in with a hammer. The recommended bore size is usually listed on the packaging or directly on the anchor itself. Remember to drill the hole at least 1/4 inch deeper than the anchor to ensure a secure fit.
Use this as a template to drill through the base whenever possible. Don’t mark your holes, remove the base, install the anchor, then try to lower the base onto the anchor. This is just asking for trouble, as the slightest bump can deform the threads and damage the anchor. Then you have to start the process over with new holes and anchors.
If you want to achieve the best results, I recommend reading my previous article on drilling through concrete. It will provide valuable insights, especially if you’re not familiar with the difference between rotary and rotary hammer drills. Both tools are essential for specific jobs.
Installing concrete anchors creates a lot of dust. Properly remove the dust to ensure the anchors fit securely.
Driving in the Anchor
Once the holes are drilled and the anchors are in place, it’s time to drive them in. If you’re using high-quality anchor bolts, they will have extra metal on top to prevent the threads from distorting during installation. For cheap anchors, I recommend backing off the nut to avoid hammering the end bolt, which can damage the threads. Instead, use a hammer to strike the nut and protect the threads.
Premium brands are on the left and cheap brands are on the right. Premium branding is designed to prevent threads from deforming as you screw in.
This is how you position the nut when you hammer a good brand anchor in.
Put the nut on a cheap anchor like this so you can hammer the nut, thus reducing the chance of deforming the threads.
Drilling in the anchor is much more than hammering it in after the hole is drilled. Care must be taken not to mushroom the end of the bolt. If it warps, the petals will bind and cause the anchor to rotate in the hole instead of expanding.
Please note that once you’ve installed wedge or sleeve anchors, removing them is not an easy task. You’ll need a grinder or reciprocating saw to cut them away. However, in some cases, like the Florida Outdoor Sculpture Competition in Lakeland, we drilled all the way through the 6-inch thick concrete pad to install the new sculpture.
Setting the Anchors and Tightening the Nuts
After you’ve installed the concrete anchors, it’s time to tighten the nuts. You can use a socket set or a ratcheting open-end wrench for this purpose. However, if you want to save time and effort, especially when dealing with larger 3/4-inch or 1 1/8-inch bolt heads, investing in a cordless impact wrench is a smart move. It significantly speeds up the process of tightening the concrete anchors. If you’re unsure about the difference between an impact driver and an impact wrench, be sure to watch the video we made on the subject.
Use an impact wrench to shorten the tedious work of tightening fastener nuts with a wrench or socket.
Large Diameter Concrete Anchors: Strength and Versatility
Another type of concrete anchor worth considering is the large diameter anchor, including the heavy-duty Tapcon brand. These anchors offer several advantages over other types. For one, they can be removed, although the hole cannot be reused once the anchor is taken out. Provided the anchor goes into a newly drilled hole, you can reuse Tapcon concrete screws for non-critical indoor workloads.
Large Diameter 3/4″ x 8″ Concrete Anchor
Another benefit of large diameter concrete anchors is that they stay closer to the concrete edge compared to wedge anchors since they don’t expand. According to Tapcon, their large diameter concrete anchors are 20% stronger than wedge or sleeve anchors. Plus, they can be installed quickly. However, keep in mind that anchors of this size require power tools for installation.
Lag Shields, Lead Shields, and Plastic Anchors: Lightweight Options
For lighter anchors, lag shields (also known as lead shields) and plastic anchors are suitable choices. Lag shields work similarly to plastic anchors. You drill a hole of the correct size, insert the anchor, and drive in the screw, causing the metal or plastic to expand and wedge into place. However, plastic anchors are not recommended for concrete applications where higher pull-out strength is required. They work well for lightweight objects, typically supporting weights ranging from 30 to 50 pounds, depending on the size of the anchor.
Lead Shields and One Reason to Use Them – Screw Eyes
Plastic anchors are usually not strong enough to anchor into concrete
Lead shields, although not as popular as wedge and sleeve anchors, still have their uses. One particular advantage of lead shields is their compatibility with screw eyes (screw eye bolts) that have the same thread as the lag. This makes them the only concrete anchors that allow this feature. For example, at the Polk Museum of Art, we have permanently placed lead shields in the brick courtyard so that, in the event of a hurricane, we can install large eyebolts in the ground and secure sculptures for the impending storm.
Tapcon Concrete Screws: Game Changers
Let’s talk about Tapcons for a moment. These little wonders have truly changed the game. During my time at the first art gallery I worked at, we had brick walls that required hanging exhibits every month or two. Drilling and installing plastic anchors were a real headache. I would have given anything for Tapcons back then, especially mount kits like the ones pictured below. Unlike plastic anchors, Tapcons didn’t leave any marks on the wall after removing the exhibit. They were discreet, leaving only tiny colored circles on the wall.
Tapcons Concrete Screws
Powder-Actuated Fasteners: Powerful and Fast
Powder-actuated fasteners, also known as Ramsets, are a special type of concrete anchor that doesn’t require drilling a hole beforehand. Instead, they utilize a .22 caliber low-velocity powder charge to drive hardened nails into concrete through wood or metal. While these fasteners are indeed fast, they can cause damage to the concrete around the nail and move the board being attached. Personally, I prefer using them in cinder block walls and reserving wedge anchors for concrete applications.
Powder-actuated fasteners and .22 caliber cartridges. These can shoot through wood, steel, and concrete.
Toggle Bolts: Often Overlooked, but Effective
When it comes to cinder block anchors, one commonly overlooked option is the toggle bolt. These anchors take advantage of the cavities in cinder blocks. To install them, you squeeze the anchor’s wings together, folding them down to the smallest possible size. Then, you drill a hole to allow the wings to pass through and pop open inside the hollow cavity. Finally, pull back on the bolt to tighten the wing and secure the bolt. Toggle bolts are remarkably strong and reliable anchors.
Summarizing the Types and Usage Methods of Concrete Anchor Bolts
So, let’s summarize the various types of concrete anchors and their usage methods. In addition to the ones mentioned in this article, there are more options available, such as hammer anchors, adhesive anchors, and epoxy anchors. However, the anchors discussed here are the ones you’ll commonly find on residential job sites. For larger commercial or industrial sites, additional types of anchors may be used.
Installing concrete anchors is easy and fun when you have the right tools. But remember, safety should always be a priority. Protect your eyes, ears, and lungs, especially when dealing with concrete dust that contains silica, a known carcinogen. Take the necessary precautions and follow OSHA guidelines to safeguard your health.
Sculptor Hanna Jubran with his completed work at Lakeland’s 22nd Annual Florida Outdoor Sculpture Competition. The sculpture is secured to a concrete pad using wedge anchors to withstand Florida’s extreme weather.
Now that you have a better understanding of concrete anchors, you can confidently choose the right type for your project.