Wedge anchors are specialized support bolts used to attach fixtures such as wood two-by-fours into solid concrete. They consist of a threaded stud or anchor clip, an expansion clip, a washer, and a hex nut and are typically made of steel or stainless steel.
Unlike sleeve anchors or toggle bolt anchors, which can be used as fasteners in various types of masonry like brick or block, wedge anchors can only be used in concrete. Wedge anchors are also widely regarded as the strongest of any type of expansion anchor—those that are ⅜" in diameter have a pull-out weight of 1,560 lbs. Wedge anchors that are ¾" can handle a pull-out weight of more than 6,600 lbs. This strength is what makes them so common in many industrial settings, where wedge anchors are often used to hold down the bases of columns for storage shelves in warehouses or to bolt down new machinery on a factory floor.
Installation Guide
First, gather the necessary tools, which include a hammer drill, a hammer, an adjustable wrench, and a small brush or shop vac to clean dust from inside the installation hole. Then, follow these steps to install wedge anchors into concrete.
Step 1: Measure to determine the length of the wedge anchor
You can figure out the minimum length of your wedge anchor by adding the thickness of the material you are fastening to the minimum depth needed, allowing space for the nut and washer. However, keep in mind that it is generally recommended to insert anchors beyond the minimum embedment depth to increase the holding value of the anchor.
Step 2: Drill the hole
Start with a carbide-tipped drill bit that is the same diameter as the anchor being installed and use the hammer drill to bore a hole at least ½" deeper than the expected depth into the base material. Make sure to follow these guidelines to ensure you are drilling the minimum embedment depth:
| Wedge Anchor Diameter | Minimum Embedment Depth |
| ¼" | 1⅛" |
| 5/16" | 1¼" |
| ⅜" | 1½" |
| ½" | 2¼" |
| ⅝" | 2¾" |
| ¾" | 3¼" |
| ⅞" | 3⅞" |
| 1" | 4½" |
| 1¼" | 5½" |
When drilling, always wear proper eye protection, as small particles of concrete will be produced while working. Place a piece of heavy-duty tape on the drill bit to mark the targeted hole depth, or simply set the depth gauge on your hammer drill. Set the hammer drill to hammer mode and burrow until you reach the tape mark on the bit, or reach the pre-set depth.
Step 3: Clean the hole
After drilling, it’s important that you remove all of the concrete dust and other debris or it could hinder the holding value of the anchor when it is inserted. Use a small wire brush or a shop vacuum to ensure the hole is clean and allow the wedge anchor to achieve proper fastening.
Step 4: Install the anchor
Before installing, place the fixture you are fastening over the hole and double-check to make sure the hole in the fixture is big enough to allow the wedge anchor to be inserted through it.
After assembling the washer and nut, be sure to leave the nut flush with the top of the anchor body to protect the threads. Then, insert the wedge anchor and drive it through the material you are fastening. Tap it with a hammer until the washer and nut are flush with the surface. Then, expand the anchor by tightening the nut by hand until it fits snugly. Using a wrench, you can then turn the nut another three to four full turns until it is tight.
The following is a guide that shows the maximum torque and pull-out weight (in pounds) of the primary size wedge anchors:
| Size | Minimum Embedment | Max. Torque | Drill Bit | Pull-Out (lbs.) |
| ¼" | 1" | 5 ft./lbs. | ⅜" | 939 |
| ⅜" | 1-9/16" | 10 ft./lbs. | ½" | 1,560 |
| ½" | 2" | 20 ft./lbs. | ⅝" | 3,105 |
| ⅝" | 2½" | 30 ft./lbs. | ⅞" | 3,323 |
| ¾" | 3-3/16" | 40 ft./lbs. | 1" | 6,678 |
Note: The values above are only a guide. In general, 25% of the weights above are considered a safe working load.
Whether you’re installing walls in the concrete floor of a basement to create separate rooms or putting down support beams for an outdoor deck into concrete in your backyard, you’ll need wedge anchors to complete the job.
Remember, it’s best to carefully measure before drilling and to consider whether the wedge anchors may need to be moved or adjusted in the future. Even though wedge anchors and other concrete fasteners are usually designed to be permanent, if you plan ahead it is possible to remove concrete anchors without compromising the base material.
Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand and follow all manufacturer instructions.