How the old chimney will be modified for gas fireplace units. The framing progress is also spotlighted, including in the breakfast area and the third-floor master suite; and rebuilding the backyard retaining walls commences. Also: a chat with a struc... (more)tural engineer about one of Charlestown's most iconic structures, the Zakim Bridge; and a visit to a salvage yard that has architectural elements from the Greek Revival period.