O&S Associates provided design and oversight for the comprehensive restoration of the Belgravia Hotel, a Beaux-Arts historic landmark. The project included the restoration of terracotta masonry, window replacement, and the preservation of the cast iron canopy, earning prestigious awards.

O&S provided a comprehensive façade assessment for the historic Reading Terminal Headhouse in Philadelphia, balancing the needs of historic preservation with functional repairs for the Marriott hotel and convention center entrance.

O&S designed and managed the roof replacement at Bayard Taylor School, incorporating EPDM and metal roofing along with comprehensive building repairs to preserve this historic school structure.

O&S performed façade restoration and repairs on the historic Ritz-Carlton Philadelphia, restoring its marble veneer and glazing in accordance with preservation standards set by the Philadelphia Historic Commission.