#3 White House

Eight years later in 1909, President William Howard Taft expanded the West Wing and created the first Oval Office, which was eventually moved as the section was expanded. In the main mansion, the third-floor attic was converted to living quarters in 1927 by augmenting the existing hip roof with long shed dormers. A newly constructed East Wing was used as a reception area for social events; Jefferson's colonnades connected the new wings. East Wing alterations were completed in 1946, creating additional office space. By 1948, the residence's load-bearing exterior walls and internal wood beams were found to be close to failure. Under Harry S. Truman, the interior rooms were completely dismantled and a new internal load-bearing steel frame constructed inside the walls.