Oxon hill 

Oxon Hill, MD


Historic Structure Report

Conditions Assessment


Historic Research

A few miles south of Washington, DC and across the Potomac River from Alexandria, the 49 room estate of Oxon Hill exemplifies the wealth and power of the diplomatic elite in the 1920’s.  Sumner Welles acquired the 245 acres of Oxon Hill property in 1927 and hired architect Jules Henri de Sibour and landscape architect Ellen Biddle Shipman to design a new estate for the property.  Designed for lavish entertainment, the main first floor spaces flow through French Doors onto a broad brick patio and into Shipman’s terraced gardens.  The Welles moved into their new home in 1929 and in 1933 Sumner joined President Franklin Roosevelt’s administration as Assistant Secretary of State, eventually rising to Undersecretary of State.  Oxon Hill became a site for entertaining foreign dignitaries and diplomates throughout Sumner’s political career. 

DBA has been working with the Maryland- National Capital Parks and Planning Commission on a multi-phase project to develop a Historic Structures Report and Prioritized Preservation Plan and repair the exterior envelope, terrace and stair.  The HSR and Preservation Plan will be incorporated into a Historic Landscape Report/Historic Structures Report headed by Oehme Van Sweden Landscape Architects.  DBA is using the built envelop, along with primary and secondary sources, to write a history of the estate, describe the original design, and catalog changes over time. 

The main house is suffering from water intrusion at the roof and subsurface levels.  After conducting investigations, DBA developed design strategies to resolve these water intrusion issues.  Additionally, significant brick damage and deterioration is present in the garden’s terraces, patios and stairs.  DBA has prepared repair documents for the repointing, repair, cleaning and replacement of bricks in the garden and motor court.  All work will comply with the Secretary of the Interior’s Standards for Rehabilitation of Historic Properties and National Park Service’s relevant Technical Preservation Brief.