Wedge anchors are a type of concrete fastener designed for anchoring to solid concrete and come packaged with the correct number and size of nuts and washers Wedge anchors are available as zinc plated wedge anchors, hot-dipped galvanized wedge anchors, 304 stainless steel wedge anchors, and 316 stainless steel wedge anchor.
The wedge anchor is a commonly used type of anchor used for fastening into solid concrete because it provides exceptional holding values and is considered the most consistent of any mechanical type concrete anchor in terms of holding values. It is a versatile concrete anchor due to its wide range of diameters, lengths, and material types.
Wedge Anchor Brand Names
Wedge anchor is the generic term for a type of concrete anchor. Wedge anchor is the name of the product sold by Concrete Fasteners, Inc. whereas Hilti, Inc., of Tulsa, OK, uses the name Kwik Bolt®. Simpson Strong-tie of Pleasanton, CA calls their wedge anchor the wedge-all® and Powers, Inc. in Brewster, NY calls their wedge anchor the Power-Stud®.
How Wedge Anchors Work
Regardless of the brand name, every wedge anchor works in the same way. The wedge anchor has a clip that wedges between the body of the wedge anchor and the wall of the hole in the concrete. The wedge anchor is set after its clip has been set using the correct torque values for the diameter of wedge anchor being used.
How Wedge Anchors Are Installed
All wedge anchors are hammered into the hole in the concrete with a hammer. Once the threads of the wedge anchor are below either the surface of the concrete or the surface of the material being fastened then the wedge anchor is ready to be set into the concrete. The nut is first finger tightened and then a wrench is used to turn the nut clockwise until the correct torque is applied. The correct torque is dependent on the diameter of wedge anchor being used. Once the wedge anchor is torqued to the proper torque value for the diameter of wedge anchor being used then the wedge anchor is safely set.
Different Types of Wedge Anchors
- Wedge anchors come in a variety of types that are based on the plating of the steel and on the type of steel used to manufacture it.
- Zinc Plated Wedge Anchors – are wedge anchors made with zinc plating to give the carbon steel protection against rust. The zinc plated wedge anchor should be used in indoor applications or where moisture is not present.
- Hot-Dipped Galvanized Wedge Anchors – are wedge anchors galvanized using the hot-dipped process, which gives the wedge anchor better rust resistance than the standard zinc plated wedge anchors. Hot-Dipped Galvanized wedge anchors can be used in outdoor applications and in moist atmospheres, and are deemed acceptable for use with the ACQ treated lumber.
- Stainless Steel Wedge Anchors – There are three types of stainless steels used in the manufacture of wedge anchors: 303 stainless steel, 304 stainless steel, and 316 stainless steel. The 303 and 304 stainless steel have equal rust resistance. The 316 stainless steel is superior to both the 303 and 304 stainless steel because of it has better rust prevention. The 316 stainless steel is typically used in caustic atmospheres such as wastewater treatment facilities. The 303 and 304 stainless steel is used in wet applications or in applications submerged in water.
Hole Size Equals Anchor Size
All wedge anchors require a hole to be drilled into the concrete before the anchor is placed into position. The hole diameter is critical and must be drilled using a hammer drill and a carbide drill bit that meets ANSI Standards. The hole diameter for any wedge anchor is equal to the diameter of the wedge anchor being installed. If a 3/8” diameter wedge anchor is being installed then a 3/8” hole must be drilled into the concrete.
Each diameter of wedge anchor has a minimum embedment into the concrete at which it must be installed. Less than minimum embedment will decrease the holding values of the wedge anchor significantly, or give no holding values at all. See the technical information for the minimum embedment for each diameter at /wedge-anchor-technical-specifications.
Wedge anchors do not have a maximum embedment depth. As a rule of thumb, the deeper the wedge anchor is embedded into the concrete then the better the holding values will be. If the wedge anchor is embedded deeper than the rebar in the concrete, the holding values become even greater. The problem with deeper embedments in concrete is that rebar may be hit and drilling through rebar for wedge anchors requires a completely different set and type of bits.
Wedge Anchor Diameters
Wedge anchors come in nine different diameters. Although many companies do not make all nine diameters, Concrete Fasteners, Inc. stocks all nine diameters in their Cleveland, Ohio warehouse. The diameters are 1/4”, 5/16”, 3/8”, 1/2”, 5/8”, 3/4”, 7/8”, 1” and 1-1/4”. See the product information page for all diameters and lengths available at
Wedge Anchor Lengths
Each diameter of wedge anchor comes in different standard lengths ranging from 1-3/4” for the 1/4” diameter and up to 12” for the 1-1/4”. The lengths are the same for zinc plated wedge anchor, hot-dipped galvanized wedge anchors, 303 and 304 stainless steel wedge anchors and the 316 stainless steel wedge anchors. See the product information page for all diameters and lengths available at
Length of Wedge Anchor to Use
The minimum length of wedge anchor to be used for any type of application is determined by adding the thickness of the material being fastened to the minimum embedment for the diameter of wedge anchor being used, plus adding space for the nut and washer. The space for the nut and washer is usually equal to the size of the diameter of the wedge anchor being installed. For example, if a 5/8” wedge anchor is being installed then the space for the nut and washer would equal 5/8”.