SYSTEMS/MASONRY
Several of these requirements are applicable to all wall systems. Those concerning mortar joints,
mortar droppings, weepholes, flashing, shelf angles and ties are specific to masonry walls, and
many of these are covered in industry guidance documents. Proper techniques for placing masonry
units and tooling mortar joints are contained in BIA Technical Note 21C, the PCA Concrete Masonry
Handbook and the PCA Concrete Information IS220.01M. These include minimizing the movement
of the unit after placing in contact with the mortar, carefully filling head joints, covering newly
erected masonry with a tarpaulin at the end of the day, and wetting exposed mortar joints for four
days after filling or covering them with plastic.
Two key construction issues are keeping the cavity clean and reducing the impacts of weather on
construction. The referenced construction guidance documents describe procedures to keep the
cavity clean of mortar droppings and other foreign materials. Mortar within the cavity will create
bridges that allow water to be carried across the cavity to the backup wall, preventing effective
drainage of the cavity. Mortar droppings can also plug weepholes. Mortar droppings can be
prevented by keeping a board in the cavity below the mortar application and progressively pulling
the board up as the work is done. This technique is described in detail in the referenced
documents. The impact of weather conditions on masonry construction are also covered in these
guidance documents since both hot and cold weather impact material properties. These
documents provide specific guidance on storage and handling of materials, and the construction of
temporary enclosures to protect walls during construction.
Construction also impacts the integrity of masonry construction when time schedules and cost are
allowed to compromise quality. As pointed out above, good construction technique is required to
ensure maximum resistance to rain penetration and other aspects of performance, and good
technique must not be sacrificed for speed. The use of good design and quality materials can not
overcome excessively fast masonry construction.
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