SYSTEMS/STUD WALLS
Brick Veneer Systems
As mentioned above, brick veneer/ metal stud wall systems have been the subject of some
controversy concerning their structural performance. The questions have centered around the
relatively flexible stud wall backup as compared with systems employing more traditional masonry
backup. If the stud wall deflections are too large, the brick veneer can crack. Some have pointed
out that making the stud wall backup sufficiently rigid to avoid this problem can make the system
less economical. The corrosion of metal fasteners and brick ties is another concern with these
systems.
While there was once much discussion regarding the applicability of brick veneer/metal stud
systems, the issue is much less controversial today. BIA Technical Note 28B contains a thorough
discussion of these systems. The CMHC Seminar on Brick Veneer Wall Systems also discusses
brick veneer/metal stud systems and presents the results of a survey conducted in Canada to
determine the state-of-the-art regarding their design, construction and performance. In addition to
the concerns mentioned above, the survey also revealed concerns with the installation of air barrier
systems and vapor retarders in these walls and the adequacy of inspection practices.
It is revealing to compare the respective advantages and disadvantages of metal stud backup to
masonry backup in brick veneer walls, as identified in the CMHC report. Masonry backup offers the
advantages of a well-established track record of good performance, stiffness to lateral loads, a
continuous surface for the application of insulation, air barriers and vapor retarders, and no
problems of corrosion. The disadvantages include having a large self-weight that impacts the
structural requirements, construction being more dependent on weather conditions, complex
installation of services in the wall, and the system stiffness complicating the accommodation of
movement of structural frame. The advantages of a metal stud backup include a low self-weight
that requires lighter structural framing, rapid erection that is relatively independent of weather, ease
in accommodating electrical services in the wall, and ease in installing insulation in the wall. The
disadvantages of metal stud backup include the lack of long term performance history, the low
stiffness of the stud wall, and the susceptibility to corrosion of the metal components.
A brick veneer/metal stud system places the same requirements on the brick veneer that were
discussed in the section on Masonry, including high quality and compatible masonry materials,
mortar joints that provide a good barrier to rain penetration, flashing that is securely and
continuously attached to the backup, and good drainage behind the veneer through the cavity and
open weepholes.
PAGE 4.3-5
Previous Page
