The term expansion shield is used to describe a masonry anchor that requires the use of a bolt, lag screw or setting tool to expand the anchor once it is placed in a hole in the base material. Other than epoxy type and concrete screws, all other concrete fasteners use expansion as a means by which their holding values are derived. Different types of expansion shields have been developed over the years and all continue to have features and benefits that meet today’s application requirements.
Here is a listing of the different expansion shields’ features and benefits with links to both the technical information and product information.
Drop-In Anchor
The drop-in anchor is the newest type of expansion shield and is designed for use in solid concrete only and cannot be used in brick or block. The drop-in anchor comes in five diameters of 1/4”, 3/8’, 1/2”, 5/8” and 3/4”. It requires the use of a setting tool for expansion of the anchor in the concrete. The drop-in anchor is manufactured in zinc plated carbon steel, 304 stainless steel and 316 stainless steel. Drop-in anchors have excellent holding values and may be used in overhead applications.
Technical Information
Product Information
Installation Video
Machine Screw Anchors
The machine screw anchor was designed many years ago and works well in all masonry materials such as brick, block or concrete. The machine screw anchor comes in nine diameters of #6, #8, #10, 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. All sizes require the use of a setting tool to expand the anchor in the base material. The machine screw anchor is made of two parts: the inner threaded part made from die cast Zamac material and the outer anchor body made of a rust resistant alloy. The machine screw anchor is versatile and has excellent holding values.
The single expansion anchor works well in hard dense base materials such as concrete, brick or block. The expansion occurs in one area of the anchor body. It is very important to make sure the anchor’s expansion area is in the solid part of the masonry. The single expansion anchor come is six diameters 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. It is expanded by inserting a machine threaded bolt. The threads in the single expansion anchor are national coarse threads, therefore the bolt used must have threads that are national coarse threads. The single expansion anchor is made up of two parts: the anchor body and the expansion nut. It comes preassembled and ready to use.
Technical Information
Product Information
Installation Video
Double Expansion Anchor
The double expansion anchor works well in suspect base material because the expansion occurs along the entire length of the anchor body, which provides holding values even in the softest base materials. The double expansion anchor is manufactured in six diameters of 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. All are expanded by inserting a machine threaded bolt. The anchor has two expanding nuts (one on each end) which insures consistent and even expansion along the entire anchor body. The double expansion anchor comes fully assembled with two wire expanding rings holding the entire anchor together.
Technical Information
Product Information
Installation Video
Lag Shied Anchor
The lag shield anchors are manufactured in a short version and a long version. The short version is used in hard dense base materials and the long version is used in application where the base material is softer. Inserting a lag screw expands the lag shield; a machine bolt will not work. Both the long and short lag shield come six diameters of 1/4”, 5/16”, 3/8”, 1/2”, 5/8” and 3/4”. Lag shields are made from a zamac material, are cast in two pieces, and are preassembled into a single unit.
Technical Information
Product Information
Installation Video
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