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 structural engineer about one of Charlestown's most iconic structures, the Zakim Bridge. In the second half: beneficial insects are discussed; a front door is resized; and an outdoor garden faucet is repaired.