Anchoring to Masonry
Published by Robert Carlisle on Feb 13th 2013
When anchoring to masonry, this base material encompasses a wide range of materials and not all masonry fasteners will work in all types of masonry. As a result, there is a wide type and range of fasteners available for anchoring to masonry.
Types of Masonry
Masonry, as it relates to masonry fasteners, includes concrete, block, brick, grout-filled block and mortar joints. All of these materials are widely used in the construction of homes, buildings, and infrastructure. The type of masonry will determine the type of masonry anchor used for any specific application. Masonry anchors’ holding values are directly related to the quality of the base material that it is installed.
Types of Anchors
There are two types of masonry anchors: mechanical/expansion anchors and adhesive anchors. This article addresses the mechanical expansion type masonry anchor. Expansion anchors work by creating an outward force against the inside walls of the hole in the masonry material. The anchor creates an outward force when it mechanically changes its form as it is inserted into the hole and then expanded. This creates the outward force that produces the friction that provides the holding values. Each type of masonry anchor expands differently based on the masonry material for which it is designed.
Some applications require the anchor to protrude from the surface of the masonry while others require it to be set flush with the surface. Other applications need a head that sits flush with the surface of the item being attached. Another consideration is whether the working end of the masonry fasteners will be in solid base material, such as concrete, mortar, grout filled block or hollow block or brick.
Stud Type Anchors for Solid Masonry
- Wedge Anchor – can only be used in solid concrete and is designed for embedment in the concrete with threads protruding above the surface allowing an item to be attached using a nut and washer. The wedge anchor is expanded by turning the nut clockwise, which pulls the stud up and wedges the expansion clip tightly between the anchor body and the concrete.
- Strike Anchor – for use in solid concrete, utilizes a hardened steel pin to expand the anchor once inserted in the hole. It can be set in place or inserted through the hole in the item as it is in place. The nut and washer are used to hold the item being fastened to the concrete and is not used to set the anchor.
Flush Type Anchors for Solid Masonry
Drop-In Anchor– designed specifically for use in solid concrete and should not be used in brick, block or any other non-solid base material. Drop-in anchors are set in the concrete utilizing a set tool which is specifically designed for the diameter of drop-in being set. Internal threads are national coarse threads and are about equal to half the length of the anchor.
Stud Type Anchors for Hollow and Solid Masonry
There are not any types of anchor for hollow masonry that will just leave a stud sticking out from the surface. All of these fasteners would be described as follows:
Headed Type Anchors for Hollow and Solid Masonry
- Tapcon– masonry screws, taps threads into a predrilled hole in the masonry. It is available in both a hex washer head and flat countersunk, as well as in different lengths to accommodate different thickness of the material being fastened.
- Sleeve Anchors – the diameter of the anchor is equal to the diameter of the hole that needs to be drilled in the masonry. The sleeve anchor is the most versatile masonry anchor, and it comes in six diameters and four head styles of acorn, hex, flat or round.
- Hammer Drive – light duty fastener which utilizes a nail to expand anchor once the anchor has been inserted into the hole in the masonry. The anchor body is made from a zamac material with a large mushroom head. It is excellent for providing a bearing surface against the item being fastened. It is considered a permanent fastener because there is not a way to back out the nail once set.
- Split Drive – this anchor is one piece and comes with either a flat countersunk or round head. It is only available in ¼” diameter for light duty fastening and is set in the masonry by just sampling inserting it in the hole and striking the head until the head is flush with the surface of the item being attached. This anchor cannot be removed after it is installed.
Flush Type Anchors for Hollow and Solid Masonry
- Machine Screw Anchor – internally threaded fastener requires the use of a setting tool and the bottom of the hole to ensure proper setting in the masonry material. It can be considered a light to medium duty fasteners, has national coarse threads and can be used with a bolt or threaded rod.
- Single Expansion – provides excellent holding values and is mostly used in the hard dense material. The internal threads are all national course and it is considered a light to medium duty fastener
- Double Expansion – perfect for applications where the base material is suspect in its ability to provide adequate holding strength. This anchor expands along its entire length and provides some holding values even in the softest or inadequate base materials.
- Lag Shield – comes in both a short or long version for each diameter. The short version is for harder denser base materials, while the long version is usually used in softer masonry base materials. The lag shield requires the use of a lag screw for it to be properly set.
Each of the masonry anchors which have been described is linked to a page that will provide more in-depth information about the following topics:
Frequently Asked Questions
Product Sizes and Pricing
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All the anchors on this page are in stock in our Cleveland, Ohio warehouse and will be shipped the same day that the order is received. Your satisfaction is guaranteed or your money back. Should you have any questions or feedback, please send an e-mail directly to firstname.lastname@example.org