Washington, DC

The Mills Building


Located at 1700 Pennsylvania Avenue NW, the Mills Building sits in close proximity to the White House in the heart of the nation’s capitol. The owner undertook a project to reposition the 1966 office building by constructing a vertical addition, recladding the existing exterior, completely renovating the interior, and creating a new rooftop terrace. SGH consulted on the building enclosure design for the project.

SGH collaborated with Gensler, the architect of record, and the project team on the building enclosure design that included:

  • Replacing existing windows and coating the architectural precast concrete surrounds
  • Overcladding portions of the precast concrete wall panels with a combination of terra¬†cotta and metal panel cladding and attaching the new cladding panels to the existing architectural precast
  • Expanding the ground-level retail space by adding new curtain wall to enclose the existing arcade and adding a new entrance canopy
  • Enclosing the new three-story vertical addition with unitized curtain wall and metal panels and low-slope roofing
  • Providing new roofing and vegetative assemblies at the rooftop amenity terraces

Highlights of our work include:

  • Reviewing the proposed design for the building enclosure and helping develop details to integrate the various systems
  • Analyzing the attachment of the precast wall panels to the base building structure and developing a testing protocol to evaluate the feasibility of anchoring the new cladding to the existing panels
  • Evaluating new roofing assemblies, including amenity roof landscaping
  • Providing construction phase services, including reviewing submittals and substitution requests, witnessing performance testing of in situ curtain wall and terrace waterproofing assemblies, and helping the project team address field conditions

Project Summary



Completion Date


Project Size

BOMA 360

New Construction
Structures | Building Enclosures
Commercial | Mixed-Use
Specialized Capabilities
Repair & Strengthening | Roofing & Waterproofing

Key team members

Megan Toumanios
Megan Toumanios
Senior Project Manager
Jeffrey Kerr
Jeffrey Kerr
Building Technology Division Head, Washington, DC