We have a client interested in replacing their existing roof on a 6,000 SF building in San Francisco, CA. The existing structure has CMU walls that need to be tested to see if they have rebar, a concrete slab floor, steel trusses with a steel corrugated roof and no insulation below. The building was built at the turn of the century and is currently used as a automobile repair shop with car lifts, etc…The client would like to renovate the building for commercial office or art gallery use. We are interested interested in replacing the roof that will need to be insulated and have a descent look from below, as well as not add significantly to the weight or it will trigger a full seismic upgrade of the building. Can you please let us know what our options might be as well as cost?