OG 11-007

HPA number
HPA 11-010

Dumbarton Oaks
1703 32nd Street, NW
United States

D.C. Department of Consumer and Regulatory Affairs
Dumbarton Oaks
Addition to Orangery and skylight replacement
Review Type


Dear Mr. Steen:

In its meeting of 18 November, the Commission of Fine Arts reviewed and approved a concept design for replacement of the orangery skylights and an adjacent addition at Dumbarton Oaks, 1703 32nd Street, NW (case number OG 11-007). The Commission's approval was consistent with the report of the Old Georgetown Board (enclosed).

The Commission supported the intention to match as closely as possible the skylight details of the 1927 design by McKim, Mead & White. While the Commission members expressed concern that the addition would reduce the size of the Green Garden terrace, they accepted the operational needs of the institution and considered the design well resolved.

As always, the staff is available to assist you with the next submission.


/s/Thomas E. Luebke, AIA

Michael Steen, Director of Facilities
Dumbarton Oaks Research Library and Collection
1703 32nd Street, NW
Washington, DC 20007

cc: William Spack, Cox Graae + Spack Architects

Enclosure: Report of the Old Georgetown Board, 18 November 2010


REPORT: At its meeting of 4 November, the Old Georgetown Board reviewed and approved the concept design for renovation associated with the orangery at Dumbarton Oaks. The scope includes replacement of the 1980s skylight system and an addition for an ADA restroom and expanded pantry.

The orangery dates from ca. 1810. Robert and Mildred Bliss retained McKim, Mead & White to reconstruct the roof in 1927. Their drawings called for skylights with wood mullions at 3'-6" on center with five vertical muntins. As built, the mullions were 2'-4" on center with three vertical muntins and lapped glass, typical glazing for greenhouses of this era. In 1983, the skylights were replaced with aluminum skylights at 3'-6" on center and no muntins.

The proposal calls for replacing the 1983 work and reintroducing the 2'-4" muntin configuration. The new skylights would be aluminum with double-insulated single-light glass. Profiles would closely resemble the McKim, Mead & White design with wood applied to the interior face of the mullions and muntins.

The proposed addition would extend from the hyphen that links the orangery to the main residence, and into the terrace of the Green Garden. It would fill a void between the projecting bay window of the main residence and the brick hyphen. Details and materials of the brick hyphen would be replicated in the addition and the existing doors would be relocated in the new openings.

The gardens at Dumbarton Oaks are the most important resource in the Georgetown historic district; designed by Beatrix Farrand, they are of national significance. The architectural history of the building is one of alterations and the accretion of additions; the current proposal is consistent with this pattern. The proposed addition works well in plan and elevation as it aligns with existing elements, replicates detailing, and incorporates reveals where new walls meet old walls.

RECOMMENDATION: No objection to concept design for an addition to the orangery hyphen and skylight replacement at the orangery as documented in drawings dated 28 October 2010. File new submission of working drawings with permit application for review by the Commission.