Jamieson, Fausset and Brown on 1 Chronicles 11:8

8. Joab repaired the rest of the city--David built a new town to the north of the old one on Mount Zion; but Joab was charged with a commission to restore the part that had been occupied by the ancient Jebus, to repair the breaches made during the siege, to rebuild the houses which had been demolished or burned in the sacking of the town, and to preserve all that had escaped the violence of the soldiery. This work of reconstruction is not noticed elsewhere [Calmet].

1Ch 11:10-47. A Catalogue of His Worthies.