SYSTEMS/MASONRY
4.2 MASONRY
This section discusses wall systems in which a wythe (or wythes) of masonry constitutes the major
component of the wall. There are many systems, which may appear to be quite different, that can
be included under the general category of masonry walls. Such systems can range from a single
wythe with no exterior or interior finish to a double wythe cavity wall with brick veneer and an
interior finish of furring and gypsum. In general, most of the masonry walls of interest in commercial
buildings fall into two categories. First, there are single wythe masonry walls with one of several
different exterior and interior finishes. These exterior finishes include metal siding, stucco or paint,
while the interior finishes can range from furring and gypsum wallboard to just paint. The second
category of masonry walls are brick veneer walls which consist of a brick veneer, an air space, an
inner wythe of masonry, and an interior finish. A great deal of design and construction information
is available for brick veneer wall systems. This section does not cover brick veneer steel stud walls,
as these are covered in the next section.
Guidance on the design and construction of masonry systems is available from a variety of sources
including the Brick Institute of America (BIA), the National Concrete Masonry Association (NCMA),
the Masonry Advisory Council and the Portland Cement Association (PCA). The BIA Technical
Notes, the NCMA TEK series and the PCA Concrete Technology Today series provide very
practical information. While these materials do cover some issues of thermal integrity and envelope
airtightness, they tend to concentrate on material properties, structural issues, rain penetration and
construction techniques. While these issues are relevant to achieving good thermal performance in
masonry walls, these guidance documents do not emphasize the prevention of air leakage and
other thermal defects.
General Design Information
There is a great deal of design information available for masonry walls in publications such as the
NCMA manual of construction details by Elmiger and the PCA Concrete Masonry Handbook by
Randall and Panarese. These and other publications provide information on masonry units, mortar,
properties of masonry walls, finishes and construction techniques. Other sources of general design
information include BIA Technical Notes 21 and 21B. Grimm published a literature review on the
durability of brick masonry in 1985 that discusses the agents and mechanisms that cause
deterioration and how to increase durability through design, material selection, construction and
maintenance.
In most of these masonry design references, the discussions of thermal issues are generally not
extensive and do not stress problems of air leakage and thermal defects. While there is some
discussion of insulation systems and thermal bridging, air barriers are rarely mentioned. Some of
the guidance they provide is relevant to our discussion, including the issues of materials, crack
control, water leakage, and construction technique. This section on design information contains
brief discussions of materials and crack control, followed by a discussion of brick veneer walls since
they constitute a significant portion of commercial building masonry construction.
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