Henry N. Cobb and Michael W. Bischoff, as collaborating design partners, led the team that prepared the Pei Cobb Freed & Partners entry in the New London Embassy competition.

Ken Smith was the collaborating Landscape Architect.

Specialist consultants who assisted in formulating the proposal were:

Jaros Baum & Bolles
(mechanical / electrical / IT / plumbing / fire protection)

Viridian Energy & Environmental, LLC, and Ramboll UK Ltd. (sustainability)

Leslie E. Robertson Associates and Weidlinger Associates, Inc. (structural engineering)

Langan Engineering & Environmental
(civil / geotechnical / environmental engineering)

Ducibella Venter & Santore (security)

Schirmer Engineering Corp.
(fire and life safety / accessibility)

George Sexton Associates (architectural lighting)

Van Deusen & Associates (vertical transportation)

Lerch Bates, Inc. (building maintenance)

Ramboll UK Ltd. (traffic)

Gardiner & Theobald (cost estimator)

The Manser Practice (UK–based associate architect)

Selected competition boards
Site Plan
Sustainability Features

Design Philosophy

Introduction
The move from Grosvenor Square to Nine Elms will cast the U.S. Embassy in an entirely new role as a physical presence in its host city. The existing Embassy enjoys a privileged position in a well-established and highly valued urban context—a place of honor that is appropriately emblematic of the special relationship between the United States and the United Kingdom. Yet precisely because of its privileged status, the Grosvenor Square site limits the Embassy’s role as a work of architecture to that of enclosing the Square with a building whose first obligation must be to respect and preserve the scale and quality of an historic district. In contrast, the urban context of the Nine Elms site, a regeneration area bordering the south bank of the Thames, is open and as yet unformed; its transformation from industrial zone to mixed-use district has only just begun. Herein lies a threefold opportunity that defines the challenge of this design commission and its appeal to the imagination: an opportunity to assert the presence of the London Embassy on a larger urban stage, to create a catalyst for regeneration and to set a standard of quality for future development in the surrounding area. The move to Nine Elms thus constitutes an invitation, indeed a command, for the Embassy to reinvent itself and thereby to reaffirm the special relationship in a new and more powerful way.

Embassy Concept
Our design proposal has been shaped by our belief that the New U.S. Embassy should embody in its architecture a quiet but confident sense of purpose coupled with openness and generosity of spirit. This aspiration has informed the two key decisions that underlie our design: first, that the Embassy need not and should not clamor for attention or seek primacy through height in competition with the tall buildings that are likely to spring up nearby; and second, that the Embassy precinct should be conceived as an integrated whole in which building and landscape forge a lively engagement with each other and with the surrounding urban scene. In keeping with these principles, we have envisioned the Embassy building as a pavilion occupying the center of Embassy Square—an urban space that we interpret, following London tradition, to include the entire Embassy property together with its surrounding streets. Embassy Square will be a focal point of the new linear park proposed in the Vauxhall Nine Elms Battersea Opportunity Area Planning Framework, and will give this new park its principal window to the Thames. It will also mark the crossroads between the east-west linear park and an important green link extending southward from the river through Embassy Square to the Wandsworth neighborhood beyond.

Embassy Pavilion
The Embassy Pavilion as we have envisioned it is composed of two distinct parts: a two-story stone-clad base—hereinafter referred to as the lower register—housing principally those spaces and functions that welcome the public, together with related staff work areas; and an eight-story glass-sheathed volume—the upper register— rising above the base to house the Embassy’s internal departments and related service spaces. The architecture of the lower register is characterized by features that are functionally specific, boldly rhetorical and actively engaged with the surrounding landscape, while that of the more compact upper register is functionally nonspecific and promotes a posture of serene detachment, quietly but memorably addressing the river and city beyond. The Embassy Pavilion thus conceived affirms the dignity and representational role of the diplomatic presence while openly and generously engaging its urban context in a manner that substantially mitigates the negative impact of required security measures.

It should be noted that by limiting the height of the Embassy Pavilion to 45m (+50 A.O.D.), nearly 30m below the maximum height of the established envelope (“the iceberg”), we have assured compliance with the right to light of neighboring properties and addressed the concerns of English Heritage about the Embassy’s potential impact on the Westminster World Heritage Site.
 
Embassy Square
There is nothing residual about the open space surrounding the Embassy Pavilion: on the contrary, we envision Embassy Square as an eventful and multifaceted landscape, comprising a number of functionally and visually distinct outdoor rooms, each of which has a well-defined character complementary to its use. The most public of these landscaped spaces is Embassy Plaza, a generous granite-paved gathering place, bounded on two sides by streets, that engages the new linear park and is strategically located for convenient access both by car and on foot. From Embassy Plaza, two separate gatehouses provide access, with required security screening, to the Embassy and to the Consular Section, respectively. But rather than arriving immediately at these destinations after passing through the gatehouses, visitors are invited to enjoy intermediary outdoor spaces, the Embassy Forecourt and the Consular Garden—two very different spaces well-suited to their very different roles in serving visitors to the Embassy.

Upon entering the Embassy Forecourt, with its view of the Thames framed by a stone pier bearing the Great Seal, the visitor’s sense of arrival is dramatized by the monumentally scaled Embassy Porch, which reaches out from the body of the building in a gesture of welcome that celebrates and invites access to the two-story-high main Lobby, Grand Stair and other representational spaces within. The Embassy Porch and Grand Stair together create a memorable and welcoming image when viewed across the Embassy Lawn from Nine Elms Lane and from the River beyond.

Visitors to the Consular Section, upon entering the Consular Garden, encounter a welcoming gesture of another kind: a Consular Porch that stretches across the entire 75m-long south front of the lower register. The two-story-high stone piers and suspended bronze and glass canopies that comprise the Consular Porch provide shelter for those waiting outside and sun shading for those waiting inside the Consular Section. At the same time, the Consular Porch overlooks and frames the richly landscaped Consular Garden, with its seasonal plantings and wisteria arbor, where visitors are invited to stroll at leisure before and after they attend to their business within.

Throughout Embassy Square, the design draws on shared landscape traditions of the United States and the United Kingdom. It reflects an openness and green character suited to the Nine Elms site and the nearby Thames River. The landscape is intended to be open, elegant and understated reflecting contemporary concerns for sustainability, diversity and local context. Within this larger context, small garden spaces and a collection of specimen trees provide places of repose and reflection.

Lower Register
From the foregoing overview, the strategic importance of envisioning the Embassy Pavilion as two distinct yet interdependent sections—a lower and an upper register—is self-evident. This strategy has allowed us not only to maximize the area of the first two floors, as is programmatically ideal, but also to concentrate the rhetorical “voice” of the Embassy in the architecture of the 11m-high lower register, thus enabling the building to speak directly and sympathetically to its landscaped setting and its future neighbors bordering Embassy Square. To this end, the material palette of its exterior walls bespeaks dignity, strength and permanence together with openness to and respect for its urban setting: broad bands of warm English limestone alternating with narrow bands of light gray American granite are further enlivened by a varied array of glazed openings, whose transparency is enhanced by the use of low-iron glass set in bronze-clad frames. The two porches with their accompanying glass walls celebrate those interior spaces of the Embassy that invite public access: the main Lobby, Grand Stair, Gallery, Multipurpose Room and Consular Waiting Rooms. In this way the design grants primacy to the spaces and activities of the Embassy that are intended to serve a wider public.

Upper Register
Complementary to the lower register, with its varied fenestration and celebratory porches, is the Embassy Pavilion’s compact, uniformly glazed and resolutely nonrhetorical upper-register volume—formed in plan from an equilateral triangle each of whose sides has been shaped into a curve by a tangential circular arc centered on the opposite apex. The upper seven floors of this eight-story volume are further encased in an outer sheath of glass, curved in section as well as in plan. The resulting multilayered envelope, which has a striking depth and richness, not only brings significant environmental benefits, as described below, but greatly enhances the volume’s posture of quiet purposefulness: a hovering presence seemingly unconcerned with the particularities of its context. Yet this air of nonchalance is deceptive: the upper-register volume has in fact been carefully oriented so that one side is parallel to the Thames, directly addressing St. George’s Square on the opposite bank; a second is parallel to and addresses the prevailing geometry of Embassy Plaza; and the third frames a staff dining terrace overlooking the Consular Garden. Thus the Embassy Pavilion’s upper register makes subtle but important acknowledgement of both its local and its larger urban context.

Upper Register Building Envelope
The upper register of the Embassy Pavilion is enclosed by a multilayered envelope composed of three key elements: an exterior surface of glass, curved in both plan and section; an array of vertical blinds housed within a cavity varying from one to two meters in depth; and an inner window wall composed of insulating glass panels set in bronze-clad frames. The exterior surface, comprising triangular panels of laminated tempered glass contained within a diagrid of stainless-steel glazing members, is mounted on a similar diagrid composed of steel pipes braced laterally at each floor level and supported vertically by steel outriggers at level 4. The cavity behind the glazed diagrid contains horizontal gratings at each floor level; dampers are situated below the gratings at every other floor, and exhaust fans are located at the top of the cavity. The inner window wall is the air and moisture barrier of the ensemble. This glass is an insulating unit with a low-E coating (all the glass substrates are low-iron glass), and the inner wall framing is clad in bronze. This multilayered envelope allows for the appropriate modulation of indoor-outdoor light and heat environments while maximizing the benefits of natural light and views. In the heating cycles the dampers close, and the envelope functions as triple glazing. During the cooling cycle the dampers are open and air circulates through the cavity, removing heat from the blinds, which are programmed to block unwanted solar energy and glare year-round.