Renovations

Opened in 1932 on Capitol Hill in Washington, D.C., the Folger Shakespeare Library is home to the world’s largest collection of works by William Shakespeare, including 82 First Folios—the first printed editions of Shakespeare’s collected plays. In addition to rare books, manuscripts, and artwork, the Folger serves as a museum, research library, and performing arts venue, welcoming scholars and visitors from around the world.

Safeguarding these irreplaceable materials requires precise, carefully managed environmental conditions, particularly in the Library’s vaults, Reading Room, and Exhibition Hall.

Advancing Environmental Control for Rare Collections

Mueller Associates was engaged to design and implement targeted upgrades to the building’s HVAC systems to improve temperature and humidity control in critical collection and public spaces. The work focused on the vault areas where the First Folios and other rare materials are stored, as well as the Reading Room and Exhibition Hall—spaces characterized by dense, highly variable occupancy and strict preservation requirements.

Mueller modified and upgraded multiple existing air handling units serving the Rare Collections Storage Areas, Reading Room, and the 3,564-square-foot Exhibition Hall. These improvements were designed to stabilize environmental conditions, reduce seasonal humidity swings, and enhance long-term preservation performance.

Engineering for Preservation Performance

Following detailed testing and analysis, Mueller designed improvements to the dedicated outdoor air system serving the vault areas, including upgrades to cooling and dehumidification capabilities to more effectively depress the dew point—an essential factor in protecting paper-based collections. The firm also engineered the replacement of an outdoor air unit and a low-temperature chilled water system to improve humidity control across multiple zones.

Additional scope included the creation of new automatic temperature control zones for conference spaces, offices, and the Tea Room; new lighting for Deck B collection areas; and the relocation of stormwater piping to support the upgraded systems.

Construction Within an Active Landmark

All work was completed while the Folger Shakespeare Library remained fully occupied and operational. A compressed construction schedule and off-hour work minimized disruption to scholars, performances, and daily visitors. The engineering solutions were carefully integrated within the historic building, respecting its architectural character while significantly improving environmental performance.

Supporting Scholarship for Generations to Come

The completed upgrades strengthen the Folger Shakespeare Library’s ability to preserve its unparalleled collections while maintaining welcoming, comfortable spaces for research, exhibitions, and public engagement. The project reflects Mueller Associates’ deep expertise in museum and library environmental control—delivering highly specialized, conservation-focused engineering solutions that remain largely unseen, yet are essential to the stewardship of cultural heritage.

Read more about Mueller’s work at the Folger here.