Recognized as one of the leading consultancies in structural engineering for historic and old buildings, Old Structures provides reports, drawings, and specifications that give detailed guidance to owners, designers, and contractors, enabling the preservation, restoration, and alteration of landmarked and other older structures. Donald Friedman, Marie Ennis, and Michael Lo, the firm’s principals, are widely acknowledged as experts in this field, known both for the breadth of their experience and for their contributions to advancing the knowledge and practice of this specialty.