Complex sentence: Sullivan's influence can also be seen in the floral pattern of the Richard Bock plaster frieze on the home's third floor, although during the 1970s, restoration work--which utilized sandblasting--destroyed much of the detail on the frieze.
Split into simpler sentences: Sullivan's influence can also be seen in the floral pattern of the Richard Bock plaster frieze on the home's third floor. During the 1970s, restoration work--which utilized sandblasting--destroyed much of the detail on the frieze.