| Wedge Anchor Introduction | | | | variety of lengths. The length required needs to |
| "Wedge Anchor" is a generic term for a type of | | | | be determined for each application and is |
| anchor used to fasten a variety of materials to | | | | dependent upon the thickness of the fixture to |
| concrete. Some companies have different brand | | | | be fastened, plus the minimum embedment. To |
| names for their wedge anchors such as Kwik | | | | determine the length of anchor needed, simply |
| Bolt, Power Stud and Thunderstud. The different | | | | add the thickness of the fixture to be fastened |
| brands of wedge anchors all work on the same | | | | to the minimum embedment for the wedge |
| principles, are made from the same basic | | | | anchor diameter being used, plus the thickness of |
| materials, and provide similar high quality | | | | the nut and washer (typically the diameter of the |
| performance. | | | | anchor is close to the thickness of the nut and |
| What is a Wedge Anchor? | | | | washer). |
| Wedge anchors consist of two separate pieces | | | | This will give you the minimum length of anchor |
| that are permanently pre-assembled into a single | | | | required. Using a longer wedge anchor than |
| unit. The first piece is a carbon steel rod that is | | | | necessary will increase the holding values, but |
| threaded for a portion of its length. The opposite | | | | may increase your risk of drilling into rebar |
| end, the installed end of the anchor, has a | | | | embedded in the concrete. |
| necked-down diameter, or conical space, that | | | | Wedge Anchor Installation |
| tapers outward back to the rod's full diameter. | | | | The installation of the concrete wedge anchor can |
| The second piece of the wedge anchor is a steel | | | | be completed by following the steps below: |
| clip, or sleeve, that is permanently assembled | | | | 1. Determine the correct length of wedge anchor |
| around the conical section of the rod. Each wedge | | | | required to ensure that the minimum embedment |
| anchor also requires a nut and washer to | | | | is met and ensure that the wedge anchor fits |
| complete installation. | | | | through the hole in the fixture. The washer should |
| Wedge anchors can be used in numerous | | | | also be larger than the fixture hole. |
| applications as long as the base material is solid | | | | 2. Using the hole in the fixture as a template, |
| concrete. Unlike many other concrete fasteners, | | | | carefully drill your holes using a hammer drill and |
| the wedge anchor cannot be used in brick or | | | | carbide-tipped masonry bit. The drill bit diameter |
| block. | | | | should be the same as the wedge anchor's |
| The wedge anchor is simple to use and is available | | | | diameter. It is imperative that the hole be cleared |
| in a wide variety of diameters and lengths. Wedge | | | | of all dust and debris. This can be accomplished by |
| anchors can be used in both light and heavy duty | | | | using a wire brush, compressed air or vacuum. |
| applications. A 1/4" x 1-3/4" wedge anchor, for | | | | 3. Place the washer and nut on the anchor, turn |
| instance, would be utilized in a light duty application, | | | | the nut a couple of turns. Not fully threading the |
| while a 1-1/4" x 12" anchor would be used in a | | | | nut protects the threads of the wedge anchor |
| situation that requires a heavy duty anchor. | | | | when hammering into the hole. |
| How Does a Wedge Anchor Work? | | | | 4. Insert the wedge anchor into the hole through |
| Again, wedge type concrete fasteners are | | | | the hole in the fixture. |
| designed for use in solid concrete only. They are | | | | 5. Carefully hammer the anchors into each hole |
| designed to go into a pre-drilled hole in concrete. | | | | ensuring that the threads go below the surface of |
| Once installed, these wedge anchors can not be | | | | the concrete or past the edge of the fixture, and |
| removed without destroying the concrete. The | | | | that minimum embedment is met. |
| size of the anchor is always equal to the size of | | | | 6. Tighten the nut - finger tight. Use a wrench to |
| the hole that needs to be drilled into the concrete. | | | | tighten the nut 3 or 4 turns, or use a |
| The tolerance between the hole and the anchor is | | | | torquewrench to ensure they are tightened to |
| very tight. As the anchor is hammered into the | | | | the required torque value. Do not over-torque, as |
| hole, the clip is recessed in the gap of the conical | | | | theanchor will either spin in the hole or pull out of |
| space, allowing the anchor to penetrate the hole. | | | | the hole. |
| To set the anchor, the rod must be pulled-up | | | | Please view this Wedge anchor installation video. |
| (which occurs while the nut is being tightened), | | | | Wedge Anchor Torque Values |
| making the clip move outward on the tapered | | | | Wedge anchors require a minimum torque to set. |
| space, wedging itself between the rod and the | | | | Do not tighten the nut as tight as possible. When |
| wall of the hole. | | | | setting a wedge anchor, it is important that the |
| Since the hole tolerance is critical in the | | | | nut only be screwed on finger tight. Each anchor |
| performance of the wedge anchor, it is important | | | | diameter has a required torque value to which it |
| that the correct drill and drill bits are used. A | | | | must be tightened. |
| hammer drill should be used rather than a | | | | Length Identification Chart |
| standard power drill because it creates a better | | | | Once the anchor is properly set, all that is |
| quality hole. A carbide-tipped masonry bit should | | | | protruding above the concrete is the nut, washer, |
| also be used because they are specifically | | | | and a portion of the threads. The diameter of the |
| designed for use in hammer drills and meet ANSI | | | | embedded anchor can easily be determined by |
| standards. | | | | simply measuring the stud. The length of the |
| Wedge Anchor Holding Values | | | | anchor, however, can be difficult to determine |
| When anchoring into concrete, wedge anchors are | | | | because the depth of embedment may not be |
| an excellent choice because of their holding values. | | | | known. To help identify the length of an installed |
| The holding power of the wedge anchor, as with | | | | anchor, an identification code has been developed. |
| any anchor, is always dependent on the quality of | | | | A letter is stamped on the end of the threaded |
| the concrete. As a rule of thumb, a safety factor | | | | portion of the wedge anchor to easily determine |
| of 4:1, or 25%, is generally accepted as a safe | | | | the length of the wedge anchor after installation. |
| working load. Holding values are also derived from | | | | This letter corresponds to the overall length of |
| the depth of the embedment- the deeper the | | | | the anchor (in inches). |
| embedment, the better the holding values. The | | | | Wedge Anchor Material Specifications |
| wedge anchor must be embedded into the | | | | Concrete wedge anchors are available in different |
| concrete up to or past the minimum embedment | | | | types of steel as well as different plating. The |
| depth to obtain published holding values. It is also | | | | type of steel and plating to use is based on the |
| essential to ensure that the anchors are not | | | | application's environment. Zinc-plated carbon steel |
| placed too close together or too close to an | | | | wedge anchors are used in interior applications, |
| unsupported edge. | | | | where corrosion is not much of a factor. The |
| The pressure exerted on the concrete by a | | | | anchor, nut, washer, and clip are all made of |
| wedge anchor can be best described as | | | | zinc-plated carbon steel. This type of plating is not |
| cone-shaped, with the small end of the cone being | | | | recommended for use in ACQ treated lumber. |
| the inserted end of the anchor and the large end | | | | Hot-dipped galvanized wedge anchors are suited |
| of the cone being at the surface of the concrete. | | | | for exterior applications where corrosion from |
| If two wedge anchors are set too close together, | | | | water or moisture is a concern. The anchor, nut, |
| the pressure from the two anchors would | | | | and washer are all made of carbon steel and are |
| intersect, decreasing the holding values of both | | | | hot-dipped galvanized. The clip is made of 303 |
| anchors. These same factors apply when placing | | | | stainless steel. Hot-dipped galvanized wedge |
| an anchor near an unsupported edge. It is possible | | | | anchors are acceptable to use in ACQ treated |
| for the concrete to crumble under pressure if the | | | | lumber. |
| concrete anchor is placed too close to the | | | | Wedge anchors are also produced in two grades |
| unsupported edge. | | | | of stainless steel. The 303 stainless steel has |
| The general recommendation is that an anchor | | | | excellent corrosive characteristics for exterior |
| should be placed no closer than five diameters | | | | applications and is resistant to many organic and |
| from any unsupported edge. For example, a 1/2" | | | | inorganic chemicals, but should not be used in a |
| diameter anchor should be at least 2-1/2" from | | | | salt water environment. The anchor is made from |
| any unsupported edge of concrete. Also, two | | | | 303 stainless steel and the nut, washer, and clip |
| anchors should never be set less than ten | | | | are made of 18-8 stainless steel which is |
| diameters from each other. That is, two 1/2" | | | | comparable to 303 stainless steel. |
| diameter wedge anchors should be placed at least | | | | The 316 series of stainless steel has the best |
| 5" apart. | | | | corrosion resistance and is typically used in harsh |
| Determining the Correct Size Wedge Anchor to | | | | environments. The 316 stainless steel anchors can |
| Use | | | | also be used in a salt water environment. All of |
| The diameter of the wedge anchor required for | | | | the components in the 316 stainless steel wedge |
| an application usually depends on the size of the | | | | anchor are made from this resilient 316 steel. |
| hole in the fixture to be fastened. The "fixture" | | | | Overview |
| could be anything from a 2x4 to a piece of angle | | | | Wedge anchors are an excellent choice when |
| iron, bracket or steel plate. The hole size in the | | | | anchoring into solid concrete. These anchors have |
| fixture is most often determined by an engineer | | | | excellent holding values and are available in a range |
| based on the necessary holding values for each | | | | of materials and plating to meet the requirements |
| particular application. It is imperative to ensure | | | | of many applications. It is important to make |
| that the concrete wedge anchor fits through the | | | | certain that the correct diameter and length are |
| hole in the fixture. A 1/2" wedge anchor is, in | | | | used in each application to ensure that the wedge |
| reality, slightly larger than 1/2". | | | | anchor is set properly and safely. |
| Each wedge anchor diameter is available in a | | | | |