Historic homes are symbols of a community’s character and heritage. Their renovation and rehabilitation encourages energy efficiency while reducing the need for new construction and use of raw materials. The National Park Service states that property owners may modify or improve historic homes as long federal funds are not tied to the property and the changes do not go against state historic preservation office (SHPO) guidelines or local preservation laws. When renovating historic homes, it is common for contractors to expect the unexpected. Through careful planning and construction moisture management, contractors ensure their work does not introduce new hazards.