Concrete Stud Anchors

Wedge Purchase Wedge Anchors

Concrete stud anchors are designed for use in solid concrete only and cannot be used in other masonry base materials such as brick or block.  Concrete stud anchors use a nut and washer on the threaded end to fasten a fixture to concrete; the other end is inserted in a pre-drilled hole in the concrete.  The concrete stud anchor's most common name is the wedge anchor.

Types
Concrete stud anchors are manufactured out of a number of different types of materials or coatings that are used in different types of applications.
  • Zinc Plated - the zinc plated concrete stud anchors is manufactured from carbon steel and the zinc plated and is for dry indoor applications where moisture is not present.
  • Hot-Dipped Galvanized - concrete stud anchors manufactured from carbon steel and then hot-dipped galvanized for use in outdoor applications where moisture is present.
  • 303-304 stainless steel - concrete stud anchors manufactured from these two types of stainless steel are for use in wet environments and may be submerge in water.
  • 316 stainless steel - for use in caustic type environments where chemicals such as chlorine is present or submerged in salt water.

Available Sizes
The concrete stud anchor dimensions are described as the diameter of the concrete stud anchor as well as the length of the concrete stud anchor.  The available sizes are shown with the diameter first and then the times sign (X) and then the length for example 3/8" x 5" would describe a concrete stud anchor that is 3/8" in diameter and 5" long. 

Diameter - the diameter of the concrete stud anchor refers to the treaded end and the diameter of the nut that can be threaded on to it. 

Length - the length of the concrete stud anchor is measured as an overall length from one end to the other, including the threads and the clipped area of the stud.

Diameter to Use
The diameter of concrete stud anchor to use in any particular application is dependent on many factors, such as weight of object being fastened, depth of embedment, strength of the concrete, the diameter of the hole in the item being fastened an weather or not the diameter has been specified by and engineer.  The larger in diameter the concrete stud anchor is the more weight it is able to hold and the deeper the embedment the better the holding value may be attainable.  The higher the strength of concrete that the concrete stud anchor is placed the higher the potential holding values will be.  The predrilled hole in the fixture may also be a determining factor, if the hole in the fixture is a certain size than the diameter of wedge anchor that can be used is limited to the size of concrete stud anchor that will fit through the hole.  An engineer for the company of the item being attached determines many types the diameter of concrete stud anchor.

Length to Use
The minimum length of concrete stud anchor to use is determined by adding the thickness of the material being fastened to the minimum embedment for the diameter of concrete stud anchor, plus space for the nut and washer.  Each diameter of concrete stud anchor must be installed into the concrete at a minimum depth of embedment.

Diameter of Hole
The diameter of the hole that must be drilled into the concrete must be equal to the diameter of concrete stud anchor being installed,  5/8" concrete stud anchor requires a 5/8" hole.

Depth of Hole
The hole must be drilled a minimum of 1/2" deeper into the concrete then the concrete stud anchor will penetrate.  This will insure that the concrete stud anchor will not bottom out in the hole and will allow space for any dust that is created during the installation process to fall into making sure it does not effect the installation of the concrete stud anchor.

Concrete Stud Anchor Installation
Watch a wedge anchor installation video at or follow the steps below to install a concrete wedge anchor.

  1. With a hammer drill in the hammer mode and a carbide tipped drill bit that meets ANSI standard B212.15 that is the same diameter as the diameter of the concrete wedge anchor being installed drill a hole in the concrete.
  2. Drill the depth of the hole a minimum of 1/2” deeper than concrete wedge anchor will penetrate or 1/2” deeper then the minimum depth of embedment.
  3. Using a wire brush, compressed air or vacuum clean out the hole of all debris and dust.
  4. Thread nut on to threaded end of concrete wedge anchor, so that the top of the nut is flush with the top of the concrete wedge anchor, this will protect the threads from damage during installation.
  5. Insert concrete wedge anchor, clipped end first, into the predrilled hole in the concrete.  If the concrete wedge anchor is being installed through a hole in a fixture make sure that the hole diameter is larger than the diameter of the concrete wedge anchor being used.
  6. With a hammer strike the nutted end of the concrete wedge anchor until a minimum of 6 threads are below the surface of the concrete or the surface of the item being attached.
  7. Using your fingers tighten the nut.


 

Please remember with all fastening jobs to keep safety in mind. Always follow safety instructions on all tools, and refer to manufacturer's installation instructions when available and always remember to wear safety goggles!

Article written by: Michael Pistorino, Concrete Fastener Specialist