Why President Madison did not install a chimneypiece in the room in ca. 1797 is unknown.  The decision may have involved his inability to find a craftsman skilled enough to build the chimneypiece he wanted.  However, it's also possible that because he was called away in January of 1801 to be Thomas Jefferson’s Secretary of State, he did not have enough time to oversee the final work needed to complete his addition to Montpelier.