Updated Design Recommendations for Brick Veneer on Cold-Formed Steel Framing

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In April 2025, the Brick Industry Association (BIA) published a revision to BIA Technical Note 28B - Brick Veneer/Cold-Formed Steel Framed Walls. In addition to the typical minor modifications to reflect current codes and practices, the updated document incorporates more substantial changes to recommendations related to the cold-formed steel framing.

Over time, BIA received questions from designers asking why a difference exists in the BIA recommendations about anchored brick veneer with wood framed backings compared to anchored brick veneer with cold-formed steel backings. Understanding the history of these wall assemblies may help explain why BIA recommendations for a veneer with a backing of cold-formed steel framing were generally more stringent. Until recently, wood framed backings were limited to low-rise applications, typically those associated with single-family homes or townhouses, whereas cold-formed steel framed backings were used in larger multi-family and commercial structures. Other than the difference in application, anchored brick veneer with wood framing had an established history of good performance while anchored brick veneer with cold-formed steel framing did not.

Anchored brick veneer on a cold-formed steel backing became an option for exterior wall assemblies starting in 1968. The early assemblies were generally similar to the modern version depicted in Figure 1, with a single wythe of brick (nominally 3 or 4 inches thick) mechanically attached to a cold-formed steel framed backing with metal veneer ties spanning a prescribed cavity. Recommendations for the system were developed first by United States Gypsum, but other sheathing and cold-formed steel framing manufacturers also developed their own proprietary versions. The use of the system gained in popularity due to the benefits of early enclosure during construction and reduced weight of the system; however, unsatisfactory performance began to occur, with reports of water leakage, spalling brick, severe cracking, and failed veneer ties.

In general, these early assemblies were highly flexible, with no requirements for bracing, bridging, or doubled framing at openings. The reported wall assembly stiffness varied significantly per system. In some cases, the designers assumed composite action between the gypsum sheathing and cold-formed steel framing, shared load between the brick and cold-formed steel and included the influence of the brick veneer in the stiffness calculations. Manufacturers’ literature did not require flashing in these early systems and recommendations to incorporate a water-resistive barrier, but only in limited applications, did not occur until 1976.
BIA published its first recommendations related to this system in 1979 and did not have any input to previously published recommendations developed by others. Research programs were developed to better understand the system behavior and to inform recommendations for design and detailing. Results of testing conducted in the early 1980s at Clemson University confirmed the complexity of the system behavior. This confirmation, combined with the proprietary nature of the system that was developed by those outside the masonry industry and demonstrated unsatisfactory performance, led the masonry industry to provide conservative recommendations for deflection. These conservative deflection limits were intended to limit cracking in the brick veneer, as this was the primary means of water penetration resistance at the time.

BIA Technical Notes contain both requirements and recommendations. Presentation of requirements, such as code provisions, are written in mandatory language while recommendations are identified as such or written in non-mandatory language (“should” or “may”). The intent is to educate and supplement the expertise and professional judgement of the designer who has knowledge of project specific conditions.

Overall modifications to BIA Technical Note 28B include a reorganization of content and a change in terminology. Previously, the “Detailing” section contained the majority of content. The 2025 version contains separate sections for material recommendations and detailing recommendations. Text that remains the same between the two versions may be relocated to a different portion of the document. BIA also reduced or removed discussion about topics common to all anchored brick veneer wall assemblies or those covered in other BIA Technical Notes, such as movement provisions. With respect to terminology, previous references to “steel studs” were revised to “cold-formed steel framing” for consistency with verbiage used by the light gauge steel framing industry.

The 2025 version of BIA Technical Note 28B expands the discussion of system behavior, including a new diagram illustrating the change in load distribution on the veneer ties after flexural cracking of the brick veneer occurs. Prior feedback from practicing engineers included arguments that the L/600 deflection limit was too restrictive and not appropriate for all projects. BIA reviewed and considered the uniformly applied deflection limit recommendation of L/600 for the cold-formed steel framing.

The conservative recommendation of L/600 was intended to compensate for the lack of available research on the wall assembly and the inconsistent performance of the assembly in the field when initially introduced. The value was a compromise compared to other deflection limits under consideration. The more stringent deflection limit aimed to constrain the width of any cracks that developed in the brick veneer during service.

At the time of the original BIA recommendations in 1979, avoiding veneer cracking, if possible, or severely limiting the size of cracks served as the primary means of moisture resistance. Such approaches are now less essential given the more robust materials and detailing used within the contemporary drainage wall.

In the paper, “Addressing Maximum Design Deflection for Cold-Formed Steel Framing When Used as a Backing for Brick Veneer,” part of ASTM STP 1612 Masonry 2018: Innovations in Collaborative Research, Development and Applications, Clark et al, proposed an alternative approach based on an assumed maximum crack width of 0.05 inches in the veneer. Starting with a maximum crack size as the performance criterion and including the mechanical play of the veneer ties, the maximum deflection of the cold-formed steel framing can be determined. Using this method, deflections up to L/360 in the cold-formed steel framing can be justified. Although a formal determination of allowable crack widths has not been established, available literature suggests the proposed maximum value of 0.05 inches does not impair the structural performance of the veneer. The cracks in question develop in response to lateral loads, which are inherently transient. As such, the cracks are not static and will open and close to varying degrees based on the magnitude of the event.

The changes in the BIA Technical Note 28B are not meant to supersede the existing L/600 deflection limit, but to expand the deflection limit options for designers. Deflections between L/360 and L/600 can be used, as appropriate for the project. Precedent and acceptable performance history for deflections up to L/360 exists. For instance, the National Building Code of Canada historically required a maximum deflection of L/360 for cold-formed steel backings behind anchored brick veneer. However, it decreased the maximum deflection to L/600 or L/720 in the early 1990s based on research results published prior to that period and returned their requirements to L/360 in 2005.

A significant change in the 2025 version of BIA Technical Note 28B relates to the size of the cavity and the related requirements for veneer ties. In the 2016 version of TMS 402 - Building Code Requirements for Masonry Structures (TMS 402), the cavity width prescriptive limit increased from 4-1/2 inches to 6-5/8 inches. This dimension represents the distance between the face of the cold-formed steel framing to the back surface of the brick. The increase in cavity width allowed for the inclusion of additional continuous insulation to meet the requirements of the energy code. In order to support the larger permitted cavity width, TMS 402 included new requirements for veneer ties to be used in cavities between 4-5/8 and 6-5/8 inches in width. These requirements primarily consist of increased sizes for wires and plates used in the veneer ties, which are outlined in the new Table 1 of BIA Technical Note 28B. Detailing recommendations for flashing within the cavity were simplified to focus on conditions specific to this type of wall assembly and include discussion of mortar dropping collection devices, which have become a common component in the assembly, although not required.

Since the publication of the previous version of BIA Technical Note 28B, the energy code now mandates the use of continuous insulation on the exterior of metal-framed walls for nearly all cases. Insulation placed outboard of the cold-formed steel framing reduces thermal bridging, improving the overall thermal resistance of the wall assembly. Newly added text discusses the requirements for insulation placed within the anchored brick veneer cavity and provides examples of the insulation types commonly used in this application. In addition, BIA Technical Note 28B updated all relevant details to include continuous insulation within the assembly and include new details depicting a stand-off shelf angle, an assembly that allows for support of the brick veneer with less interruption of the insulation.

Revisions to the existing text regarding parapet walls removed a recommendation against using cold-formed steel to frame a parapet but added a caution regarding framing such a parapet using balloon or bypass framing due to the difficulty in creating or maintaining continuity of the insulation, air barrier, and/or vapor retarder across the interface.

Over the years, engineers specializing in cold-formed steel design provided feedback regarding some of the recommendations in the Technical Note, indicating they were inconsistent with the state of the cold-formed industry. BIA considered this feedback when revising BIA Technical Note 28B.

In general, BIA Technical Note 28B defers to the American Iron and Steel Institute (AISI) and their North American Standard for Cold-Formed Steel Structural Framing (AISI S240) for the design of the cold-formed steel framed backing. Previous recommendations about welding of cold-formed steel were removed. Requirements from the American Welding Society as outlined in AWS D1.3/D1.3M Structural Welding Code – Sheet Steel should govern.

Previous versions of BIA Technical Note 28B recommended a minimum G90 galvanized coating on the cold-formed steel framing, which has since been reduced to a minimum G60. Multiple factors contributed to this change, including recommendations for corrosion protection from the cold-formed steel industry, a better understanding of building science principles in the industry, as well as improvements in water-resistive barrier/air barrier materials, installation techniques, certification, and workmanship. However, engineering judgement still applies. BIA Technical Note 28B identifies conditions such as areas of high interior humidity (indoor pools, laundries, kitchens, etc.) and coastal zones, where a minimum galvanizing of G90 may be warranted. Similar conditions requiring G90 galvanizing may also be identified as part of energy modeling or condensation analysis.

Anchored brick veneer with a backing of cold-formed steel framing continues to be a popular choice for exterior wall assemblies. It is hoped that this updated version of BIA Technical Note 28B will continue to serve as a useful resource to designers. ■

About the Author

Cortney Fried is a Managing Senior Engineer at the Brick Industry Association (BIA), where she develops technical reference documents, advocates for the industry in codes and standards activities, as well as assists designers, owners, and contractors with technical inquiries related to clay masonry construction. (cfried@bia.org)

References

[1] Clark, Charles B., Jr., Fried, Cortney L., and Bryja, James, “History of Cold-Formed Steel Framing Used as a Backing for Brick Veneer,” Masonry 2018: Innovations in Collaborative Research, Development and Applications, ASTM STP1612, ASTM International, West Conshohocken, Pennsylvania, 2018.

[2] Clark, Charles B., Jr., Fried, Cortney L., and Bryja, James, “Addressing Maximum Design Deflection for Cold-Formed Steel Framing When Used as a Backing for Brick Veneer,” Masonry 2018: Innovations in Collaborative Research, Development and Applications, ASTM STP1612, ASTM International, West Conshohocken, Pennsylvania, 2018.