Rehabilitation services and seismic retrofit for existing buildings requires a good understanding of past and present building codes to gage their performance and understand the strengths and vulnerabilities of the building structure. G&G Structures, Inc. has the analytical tools and the understanding of construction means and methods utilized for vintage buildings dating back to the early 1900's. We have invested resources to research the history of building codes and have learned when substantial changes have occurred in our evolving codes. We have completed seismic retrofit designs for many buildings that are classified as high seismic hazards such as unreinforced masonry buildings and concrete tilt-up buildings with wood framed roofs. We have also worked with building owners to reduce seismic risk for structures with non-ductile steel & concrete frames with masonry infill, wood framed buildings with soft or weak story conditions (such as tuck-under parking in multi-family housing), and wood framed structures with weak cripple walls.