The Ivy Substation, built in 1907 by the Los Angeles Pacific Railway Company, was one of the largest electric substations rail lines, which ran from downtown Los Angeles to the Pacific Ocean. It is a small historic structure of unreinforced masonry walls and a wood roof with wood trusses approximately 12’ on center. One side of the structure has a mezzanine of concrete slab over concrete encased steel beams, which originally supported the large switching gear for the electric substation. Though small, this building presented some unique problems that required equally unique solutions. Rather than attempt to brace the sidewalls with unsightly angles and 20’ diagonal bracing, a detail was created to stiffen the lower part of the wall that tied in to the new slab on grade. This allowed the elimination of any bracing, and gave the architect the ability to maintain most of the look of the original brick wall on the interior of the building. Air conditioning ductwork was placed below grade in order to preserve the appearance of the wood truss roof structure, where the ducts were originally to be placed. In addition, some new concrete block walls underneath the mezzanine slab, as well as shotcrete applied to small portions of the unreinforced masonry walls, allowed us to strengthen this historic structure with minimal impact to its historic appearance.