William L. Slayton House

Pei and William L. Slayton first crossed paths around the middle of the 1950s in the office of the New York developer William Zeckendorf, where both worked on urban renewal: Pei headed architecture, while Slayton, a vice-president, ran the redevelopment of Washington's Southwest area, then the office's largest project. It was in 1958 that Slayton turned to Pei for a house of his own. Pei said yes on one condition, which Slayton recalls in his memoirs: the house would have a major design feature, and an expensive one. Slayton worked closely with Pei's firm on the design. President Kennedy named him Commissioner of the Urban Renewal Administration in 1961, and he stayed in the post until 1966.

In 2002 the owners of the time had the house renovated under the architect Hugh Newell Jacobsen: the systems were updated, the exterior stayed as it was apart from the paving of the rear patio, and the smallest bedroom, in the centre, was opened to the hallway to become a library. Listing on the National Register of Historic Places followed in 2008.

More recently the architect Robert Gurney carried out a full renovation and addition, overseen by Washington's Historic Preservation Review Board. The house was taken back to its wood framing, brick walls and concrete vaults; services, insulation, roofing and glazing were renewed, and the new windows match the original details exactly, following Pei's drawings. Close to 1,000 square feet (about 90 m²) were dug out beneath the dining room, with a new deck; across the deck, beside the alley, a two-storey structure pairs a garage with a wood-and-glass office above it, wrapped in perforated metal screens.

With Pei's weekend house in Katonah, New York, and the Tandy House in Fort Worth, it is one of only three houses the architect ever designed.

Three barrel vaults of concrete cast on site form the roof. From the street, they alone rise above a 7-foot garden wall (about 2.1 m), set 18 feet (about 5.5 m) back from the sidewalk, which hides nearly all the rest of the house. The front (south) and rear (north) are almost transparent. On the street side, the single-storey facade is split into three bays 9 feet wide (about 2.7 m) and 13 feet high (about 4 m), topped by concrete arches; the brick piers between them, set mostly outside the glass, carry the vaults past the plane of glazing and shade the living room in summer. The side walls, nearly blind, are pale red brick with a rosy tone.

The lot falls 14 feet (about 4.3 m) from the street to the back, which allows a split-level plan: the entrance is level with the street; originally the kitchen and dining room lay half a level lower and the bedrooms half a level higher. The plan rests on three modules 10 feet wide (about 3 m). As a counterpoint to the strict symmetry, the entrance is at the side.

The living room measures 30 by 21.3 feet (about 9.1 by 6.5 m) and is 13 feet high (about 4 m); a fireplace sets it off from the entrance. At the time of listing, in 2008, the vaults over the living room and bedrooms were of plastered, painted concrete.

The house is private and not open to visits. From the street, the garden wall hides it almost entirely; only the three concrete vaults show above it.