Brick anchors are fasteners that attach an item to brick or a mortar joint in a brick wall. Brick anchors are different from concrete fasteners because the base material of brick is most commonly found to have hollow space, unlike concrete that is solid. The hollow space requires the brick anchor to be versatile enough to obtain holding values in the hollow areas of the brick.
The sleeve anchor is the most commonly used male expansion brick anchor and it provides the most consistent holding values. The design of the sleeve anchor allows for the anchor to expand over a greater surface than any other expansion type anchor. This gives the sleeve anchors the ability to expand properly in the hollow sections or solid sections of brick. The sleeve anchor can also be used in the solid mortar joints. It is important to remember that the ultimate holding value of the sleeve anchor is dependent upon the quality and quantity of mortar. The versatility of the sleeve anchor’s range of applications comes with only one drawback, which is that it has less shear strength than the same size female type anchor. The sleeve anchor’s designated size is equal to the outside diameter and the stud is smaller. For example, a 3/8” sleeve anchor has a 5/16” stud, thus giving the sleeve anchor the shear strength of a 5/16” anchor and not of a true 3/8” diameter.
Available diameters- The sleeve anchor comes in six diameters and in a number of different lengths for each diameter depending on the application. The minimum length of sleeve anchor to be used is determined by adding the thickness of the material being fastened to the minimum embedment of the diameter of sleeve anchor being used.
Available head styles- Sleeve anchors are available with a number of different head styles: acorn head, hex head, round head and flat head. The acorn head is hex with a finished acorn head; the hex head is the standard hex nut; the round head is slotted for use with a straight screwdriver; the flat head is countersunk phillips or slotted drive. The head style to use is determined by the particular application in which the sleeve anchor will be used.
Sleeve Anchor Lengths-The length of the sleeve anchor is measured from under the head for the acorn, hex headed and round sleeve anchor. The flat-headed sleeve anchor is measured as an overall length.
Self-tapping brick anchors are most commonly called Tapcon® masonry screws are used for fastening to brick. The masonry screw is versatile because it can be used in brick, mortar joints, CMU, block or solid concrete. The masonry screw is used in brick by first drilling a hole with a hammer drill with the correct diameter carbide bit for the masonry screw being installed. The masonry screw is then inserted into the hole in the brick and turned clockwise, tapping threads into the brick and holding the screw securely.
Masonry Brick Screw Sizes- The standard masonry brick screw comes in two diameters of 3/16” and 1/4” with lengths ranging from 1-1/4” to 6”. The minimum length of masonry brick screw to use is determined by adding the minimum embedment depth of 1” to the thickness of the material being fastened.
Head Styles- Two head styles are available with the standard masonry brick screw: the hex washer slotted and the flat countersunk phillips. All the hex washer slotted masonry brick screws lengths are measured from under the head and the flat countersunk phillips is measured as an overall length.
A number of different types of female brick anchors are available. The best one to use depends on personal preference and the specific application. Each female anchor requires a bolt and washers to be purchased separately. Many times the bolt chosen will determine the female anchor that will be used. If a lag screw is used then the lag shield brick anchor will be used. If a bolt is used with national coarse threads then any of the female brick anchors with internal national coarse threads can be used. Some of the female brick anchors require a setting tool to be used to set the brick anchor into the base material. These types of brick anchors require that the anchor is placed so that setting tool can be used to set the anchor into the brick properly.
Types of Female Brick Anchors
Machine Screw Anchors – Often called AJ’s or lead anchors, they require a setting tool that has national coarse threads. They are available in eight diameters and can be used in brick, block or concrete.
Lag Shield Anchors – These anchors are available in two different lengths of a short or long version and six diameters. The lag shield is very versatile because it can be used in very dense base material or in the base material where the holding values are suspect. The lag shield does not require a setting tool and is expanded by inserting the correct lag screw into the anchor.
Double Expansion and Single Expansion Anchors - These anchors both come in five diameters, have national coarse internal threads and have good holding values in most base materials. The double expansion expands the entire length of the anchor body as opposed to the single expansion that expands at one end. The double expansion anchor is primarily used over the single expansion anchor in applications where the base material may be soft, suspect or inconsistent.
As with any anchoring project, it is important to keep safety in mind and follow instructions carefully. Always remember to wear safety goggles, handle all tools with extra care and follow all technical specifications. This article is meant to serve only as a basic explanation of concrete fasteners. Always refer to manufacturer's instructions or consult a contracting expert during any anchoring project.