Washington’s public buildings were often converted into makeshift hospitals during the war.
Church pews became hospital beds. Fraternal lodges, private homes, hotels, schools and warehouses were turned over to medical men and their patients.
Carpenters covered church pews with scantling so floors could be laid on them and pulpits and other furnishings could be stored underneath. Hymnbooks were packed away, and kitchens were established in church basements.
Georgetown College housed patients. Even the second floor of the Patent Office became a hospital.
Source: Reveille in Washington by Margaret Leech