Phase III was the most significant phase of restoration of Graycliff, from 2006-2008. It included installation of a massive underground drainage system throughout the site. Restoration of the Isabelle R. Martin House: Roofs; chimney; Isabelle's Balcony; Darwin's Balcony, new basement floor. Restoration of the Foster House: Extensive structural repairs; roof; copper flashing & gutters; chimney; Screen Wall; North, East, West and Southwest balconies.
Phase III of restoration was undertaken with support from: New York State, the County of Erie, Save America's Treasures/The US Department of the Interior, the Margaret W. Wendt Foundation, the John R. Oishei Foundation, M& T Bank, the Seymour H. Knox Foundation, Fleet Private Clients Group, Hodgson Russ Attorneys LLP and individual members and donors to Graycliff.