Differentiating Anchoring Systems for Brick Veneer Walls
Since anchoring systems for brick veneer walls do not all function alike, some basic types of anchors and their functionalities are outlined.
By Jeremy Douglas
Anchoring systems for brick veneer walls come in a multitude of shapes and styles, but it is important to recognize that they do not all function alike. Various types of anchors offer differing benefits, such as greater strength or more adjustability to assure a sound connection. They also may offer an ability to span greater distances as the requirement for continuous exterior insulation creates wider cavities between the veneer and structural walls.
For decades, one of the most regularly used anchoring systems for brick veneer walls has been the corrugated wall tie. Referred to jokingly as a “bacon strip,” a corrugated wall tie is a strip of galvanized or stainless steel about 7/8-inch wide and around 7 inches long, with a wavy profile intended to keep the tie engaged when embedded within the mortar bed joint. The tie usually is nailed into the wood stud backup structure and bent at 90 degrees to cross the span, and then inserted into the mortar.
These are popular because of a low price point, but it is important to understand how construction codes limit their usage. In most cases, you cannot use a corrugated wall tie and remain code compliant.
Whether used in residential or commercial construction, the TMS-402 code requires corrugated wall ties to be a minimum of 22ga thickness. A thickness of 26ga or 28ga will not have the strength required to withstand typical wind loads. The code also addresses the fastener strength required when using them. As these ties typically are used in conjunction with wood stud backup, TMS-402 requires that the fastener used must have the pullout strength equivalent of an 8d common nail in wood framing.
Also, regarding construction fasteners, it is important to note that the code requires the 90-degree bend be executed within 1/2-inch of the fastener. This assures that, as the veneer wall experiences positive and negative loads, the tie will not flex and allow excessive movement of the wall.
The most important limitation to consider when using a corrugated wall tie is that construction codes allow a maximum span of 1 inch between the face of sheathing and back side of the veneer. This means corrugated wall ties cannot be used in conjunction with continuous exterior insulation, because there also is a 1-inch air space for brick veneer walls.
Two-piece brick anchoring systems
Adjustable two-piece brick anchoring systems provide a much stronger connection between wall sections. These usually consist of a stamped plate anchor that is fastened to the backup wall, with a separate wire tie formed to connect to the plate in such a way as for the two to be unable to disengage from one another. Adjustable anchoring systems are often found in block backup walls as well, though instead of being fastened to the backup, a set of stationary eyelets are embedded in every other bed joint.
Various types of these anchors can allow anywhere from 1 to 6 inches of vertical adjustability of the tie portion, in order to assure it embeds correctly in the joint. It is important to note that when using a two-piece anchoring system, construction codes do not allow for more than 1/16-inch of slack within the connecting parts.
Barrel anchors are a type of adjustable anchor quickly growing in popularity with both contractors and designers. These consist of a single barrel with a fastener on one end for either wood or steel studs, or a special fastener for concrete block or precast. An anchor with a single fastening point as found on these is faster to install and makes fewer penetrations in your water or air resistive barriers. These would have to be repaired or detailed afterward. Many of these also feature a dual-diameter barrel shape that allows a fixed gasket to be attached to the anchor. This will seal its own penetration without the use of tapes or sealants.
Any type of brick anchors used to tie a veneer wall will have to follow certain installation guidelines. Construction code requires that the tie is embedded into the brick bed joint a minimum of 1 ½-inch, but must also have a minimum of 5/8-inch of mortar cover to the exterior face of that joint. When embedding ties within the mortar joints of the veneer, it is important to remember that the joint must be at least twice the thickness of the tie itself. This is why the wire portions of ties typically are made from 3/16-inch wire, as that is the maximum diameter allowed in a standard 3/8-inch mortar joint. This does become a concern when laying brick in thinner, less visible mortar joints as we often see in some of the newer, elongated brick shapes.
So, while many different types of anchoring systems for brick veneer walls are available, they are all fairly specialized with regard to requirements found within the construction code. Become familiar with the functionality of the different types of anchoring systems for brick veneer walls. Realize that the ease of installation, both in fastening and any extra detailing that may be required against adjacent systems, should be considered when making that anchor selection.
Jeremy Douglas, CSI, CCPR, is the Director of Architectural Services for Hohmann & Barnard. Jeremy serves as the primary technical resource to the design community and has written dozens of seminars and technical resources on the subjects of moisture control, building envelope systems, reinforcing and anchoring, and masonry restoration.