For brick veneer over wood frame structures, there is a prescriptive code requirement to have a shelf angle at 30’-0.” However, to save cost and minimize thermal bridging, some design and construction teams prefer to minimize or eliminate shelf angles. To accomplish this, they use an alternative design path and develop and an engineered solution to accommodate differential movement between the veneer and the shrinking wood structure. This sometimes results in using engineered wood members to minimize shrinkage and strategically placed horizontal gaps in the veneer. These gaps are sometimes cumulative in width the higher they are located in the veneer.  There is no  height limitation for masonry veneers over CMU or concrete structures.