Expansion of Mount Vernon's Mansion

George Washington began expanding Mount Vernon while leasing the property. His first major expansion of the original one-story house with a garret began in the late 1750s. The roof was raised to create a full second story and a third-floor garret. While Washington likely left the footprint of the first floor largely intact, he reconfigured the staircase and the second floor rooms. In addition, ‘Closets,’ or one-story extensions, were added on the north and south ends of the house. Additionally, an entry in Washington's diary reported the house had four principal dependencies attached to the main house by "Pallisades" on low brick walls.⁹

Washington was away during the majority of the construction, serving in the French and Indian War. In his absence, the work was supervised through coordinated efforts by William Fairfax of Belvoir (a family friend who owned an adjoining estate), Humphrey Knight (an overseer), and John Patterson (a carpenter). While the construction was overseen by Fairfax, Knight, and Patterson, the majority of the work was actually done by Washington’s enslaved labor force.¹⁰

In addition to increasing the footprint of the Mansion, Washington elaborated the exterior by adding three striking architectural features. A two-story piazza, or porch, was constructed along the east side of the house. While porches, even two-level porches, were common in the 18th century, they tended to be of modest size, enclosing only a door. Washington’s piazza encompassed the entire east side, providing shade and shelter, which the Washington family enjoyed during much of the year.

The design of the west front included a large central pediment that showcased an oval, or oxeye, window. The pediment brought a desired classicism to the west elevation of the Mansion, and it played a key role in establishing the symmetry that Washington intended. In 1778, a cupola was added to the roof. Cupolas are typically associated with public architecture, seen commonly in academic buildings and court houses, but they are far less frequently found on dwelling houses of the period. Like the pediment, it provided a central axis for the symmetry Washington had hoped to achieve, although it does not actually sit at the centerline of the house, being somewhat inexplicably set a few feet to the south. In addition to its aesthetic function, the cupola functions as a ventilator; with its windows open, convection pulls warm air up and out of the house while drawing cooler air through open windows on the lower floors.¹⁴

In 1787, Washington designed and ordered a weathervane from Philadelphia artisan Joseph Rakestraw. Washington explained that he "should like to have a bird...with an olive branch in its Mouth. The bird need not be large (for I do not expect that it will traverse with the wind and therefore may receive the real shape of a bird, with spread wings).”¹⁵ Supporting this dove of peace weathervane, and the wooden finial and copper ball that were installed with it, is a large wrought-iron lighting rod that has protected the Mansion for over two centuries. The whole assembly completed the cupola, which had been “left so long unfinished.”