Choosing the Correct Concrete Anchor For Your Application

Jan 04 , 2021

Choosing the Correct Concrete Anchor For Your Application

Concrete Anchors

Are you looking for a way to permanently fasten something to a concrete wall? Need a device that can hold dozens of pounds without rusting away or breaking? If so, you may be in the market for concrete anchors. These simple to install devices allow you to drill a hole into a concrete wall using a masonry drill bit, insert the anchor, and then insert a screw or bolt into the anchor in order to fasten the object to the wall. This will allow you to permanently fasten heavy objects to concrete walls in such a way that takes the headache off of you. Anyone can use these for any purpose: in the home, in their business, or in the construction industry. Read on to find out more about different types of concrete anchors, their benefits and uses, and how to install each one.


Lag Shield Anchors

Lag Shield anchors are a type of screw-style concrete fastener that is specifically designed to allow lag screws to permeate concrete. If you want to install a lag screw into concrete, you must first start with a lag shield. These are available in ¼”, 5/16”, ⅜”, ½”, ⅝” and ¾” diameters, and in both short and long length varieties. Short-length varieties are better for fastening harder materials, while long lengths perform well with softer material. Lag screws, along with lag shields, are best suited for light or medium-duty fastening purposes, such as wood. Additionally, this can come in handy when fastening things to concrete walls, as the fixture itself can always be removed; only the lag shield anchor stays in place while the lag screw can simply be screwed and unscrewed to remove the fixture.


To install a lag shield, you must first start with an appropriately sized drill bit. Once that has been obtained, you’ll need to drill a hole the size of the diameter of the lag shield anchor. After ensuring that no debris remains in the hole, tap the lag shield with a hammer until the head is flush with the concrete. As you insert the lag screw, the back of the lag shield will spread open a little bit. This works to lock the whole system into the concrete and ensure the fixture will remain in place.


Drop In Anchors

Drop in anchors are a female concrete anchor, which comes in five different diameter types. Each type has one length. Some of the primary uses of a drop in anchor are to install HVAC ductwork and fire sprinkler systems; handrails; light fixtures; fire extinguishers; and shelving units. They can also be used any time a flush mounted anchor is required or a bolt needs to be removed and inserted with relative ease, because you’ll insert one into the anchor. Their holding strength is ultimately determined by a number of factors, although this type of anchor can hold large amounts of strength. This is because this anchor has smooth sides, which allows more surface area of the anchor to come into contact with the concrete and provide a better grip. The depth of embedment, psi of the concrete, and the presence of steel rebar in the structure can all affect the holding strength of a drop in anchor.


To install a drop in anchor, you’ll need to first drill a hole equal to the diameter of the anchor in width and the length in depth. Ensure the hole is fully clear, and then drop the anchor into the pre-drilled hole in the concrete with the threaded open end facing outwards and the slotted end facing into the hole. Finally, insert the matching setting tool into the anchor and hit the entire device with a hammer until the top is flush with the concrete. This will expand the back of the anchor, holding it in place.


Toggle Wing Anchors

Toggle wing anchors are primarily used to fasten things to hollow walls. This is extremely helpful when attempting to fasten devices to walls made from cinder blocks or drywall. It’s not recommended to fasten heavy objects with toggle wing anchors and hollow walls, as the entire device will likely collapse and tear through the wall. However, they are one of the strongest types of drywall anchors, and metal toggle wing anchors can hold up to 100 pounds.


To install, you’ll need to drill a hole just big enough to push the wings through. This isn’t always the easiest thing in the world, as it requires careful preparation and measurement. Typically, you’ll want the hole to be roughly three times wider than the diameter of the bolt. Once you push the toggle bolt into the wall, manually screw it into place and the wings will expand automatically. Use a screwdriver to drive the bolt into the anchor, which will pull it up against the other side of the wall, locking it into place. You must keep the bolt in place, centered in the hole, while doing this.


Hammer Drive Anchors

Hammer drive anchors are used primarily for light-duty fastening, and can typically hold around 50 pounds or fewer in a brick or concrete wall. They can be used outdoors, but do best in warm, dry indoor spaces. They come in two different diameters, 3/16” and ¼”, and in a variety of lengths. One of the drawbacks - or possibly a benefit, depending on how you look at it - is that the hammer drive anchor is completely permanent, so you will not be able to remove whatever device you fasten to the wall. Be sure when you’re installing that you’re installing it exactly where you’ll want it, because you won’t be able to move it later.


The installation of a hammer drive anchor is similar to that of the previously discussed concrete anchors. First, you must drill a hole into the base equal to the diameter of the anchor. For each type of anchor, the use of a hammer drill will create the best quality hole. One potentially helpful tip is to wrap some tape around the drill bit to identify how deep you’ll need to insert the drill. Make sure the hole is cleared of all debris, then insert the anchor into the hole. Ensure that the head of the anchor is flush with the wall, and then insert the nail into the anchor. Hammer the device into the wall until the head is flush with the anchor.


Sleeve Anchors

Also typically permanent, sleeve anchors can be used to bear extremely high volumes of weight. There are also several different types of sleeve anchors for a buyer to choose from, each that service specific purposes. They are also extremely versatile, and can be used for projects as light as hanging light fixtures and as heavy as securing platforms to walk on. The material the sleeve anchor is made from will determine where best to use it; for example, you’ll want to use stainless steel anchors in outdoor projects, and other types of metals indoors, where they will not be likely to rust.

Just like with every other type of anchor (with the exception of toggle wing anchors), you’ll want to use a hammer drill to create a hole that is the width of the specified diameter and slightly deeper than the length of the anchor itself. Again, clean the hole to ensure it is free from debris. Slide the anchor into the hole, and then tap it until it is flush with the surface. Finally, tighten the head with an appropriate tool, making sure not to tighten it too much.


Wedge Anchors

Wedge anchors are likely the most complex type of anchor discussed within this article. Unlike the other types of anchors, which come in two parts, this mechanical anchor comes in four. It contains an anchor body, just like the others, along with an expansion clip, a nut, and a washer. Also, unlike the others, wedge anchors do not require a screw or nail to be inserted into the anchor itself. Designed for use in concrete only (unlike the others, which are more versatile and can also be installed within brick, mortar, or even drywall), wedge anchors can also hold the most weight and are the most consistent type of anchor.


You install the wedge anchor the same way you would install the others: by drilling a hole with a rotary hammer and ensuring the hole is free from debris. For a better holding value, drill a hole slightly deeper than what the device requires. Place a washer over the threaded end of the anchor, then thread a nut onto the anchor body until the nut is flush with it. Then slide the anchor into the hole in the concrete. Using a hammer, hit the anchor until it is flush with the concrete.


In Summary

Concrete anchors can be used to fasten a variety of materials to concrete, brick, or mortar walls. The type of wall, as well as the material you are fastening to the wall and what you desire to do with it, will determine the type of anchor you will want to use. The anchors are all relatively simple to install, and do an incredible job of securing heavy materials permanently into concrete. For many of these anchor types, the wall will fail before the anchor does.


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