This topic covers information related to the historic treatment of wood windows, that may occur during the life cycle of a structure. Older windows in a historical or architectural structure often have qualities that demand for preservation of such windows rather than replacement. Understanding what factors are involved and how to approach treatment of older, possibly significant windows, can be understood by referring to National Park Service Preservation Brief #09, "The Repair of Historic Wooden Windows." Treatment often includes evaluation, maintenance, stabilization, repair and weatherization.