When drawing up elevations for masonry walls, in addition to locating control joints (arguably “expansion joints”) to accommodate expansion and contraction related to temperature and moisture, it is important to consider how masonry supported on lintels hung directly from deflecting structural steel will move differently from masonry that is supported directly by the building foundation. While “loose” lintels supporting masonry over openings usually rest on foundation-supported masonry at the ends of the spanned opening, hung lintels should be isolated from foundation-supported masonry in a way that allows for independent vertical movement related to deflection of structural steel. If the hung lintel overlaps the foundation-supported masonry, a soft joint similar to that below a relieving angle may be appropriate below the end of the hung lintel. And the control joint above the lintel should also be located to allow for independent movement of the two masonry conditions. Determining the location of the ends of the hung lintel is important for construction that will properly respect the different needs of the two conditions. It gets more complicated for hung lintel assemblies suspended from beams that are interrupted by columns. In any case, careful consideration should be given to the locations of control joints within the wall area that is supported by the hung lintels.
In some cases the best control joint locations for wall performance will not be the best locations for aesthetic intent. But, then, cracks are not usually attractive in appearance.