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Multiple-Wythe Unit Masonry

by admin on July 27th, 2010

A wythe, by definition, is a continuous vertical section of masonry, and is one masonry unit thick. A multiple wythe, then, is more than one vertical section of masonry laid next to one another. A picture is available to clarify. Multiple wythes are utilized in situations when added support, stability or protection is required.

A multiple-wythe masonry unit uses the same materials as the single wythe it complements. As it is only a term that is directed at the format of the masonry units, the masonry units themselves are the same as applied to any other project.

The method backing multiple-wythe construction is that of increased stability and support. Multiple-wythe constructions also allow for increased insulation and efficiency properties, as emphasized within the section titled “Environmental Considerations.”

Multiple-wythe masonry units have some similar environment considerations as single-wythe units. However, multiple-wythe units have the advantage that one face, or wall section, is not exposed and thus, is not so easily affected by outside elements. The multiple-wythe construction generally means more efficient insulation, and the small gap often left between each wythe can be another opportunity to add insulation or flashing layers.

A multiple-wythe, by design standards, is more than one vertical section of a masonry unit, laid behind or in front of one another. The design of the masonry unit is identical to a single-wythe formation. For example, there is no change in the actual design of the brick; rather the format in which they have been laid is simply altered. To further increase the strength of the units, wire truss reinforcement is often used. Interlocking materials within the cavity between wythes are also commonly utilized, for example, insulation layers.

Preparation for multiple-wythe building is similar to single-wythe construction. Of course, additional masonry units are necessary as multiple-wythe construction uses double the units of single wythe construction. Additionally, any interlocking materials to be used between wythes must be prepared.

The installation of multiple-wythe units is similar to single units, but requires double the materials and double the time and effort. Most commonly, corrugated ties connect the masonry units to the structure; however, other anchorage units can be used. In the case of extremely warm or cold conditions, special precautions should be taken.