The answer depends on the extent and nature of the modifications. The National Register recognizes the inevitability of change. Obviously, historically homes and offices did not have computers or video technology or a number of other technological innovations we now consider necessary. To ignore such developments would preclude the functional use and maintenance of most historic properties either as homes or businesses. The key to modification of historic properties is that it be done in a fashion that is sympathetic to factors and characteristics which made the property eligible.
Historic buildings are a lasting legacy for owners and communities.
Historic buildings communicate information about our history and culture and contribute to a sense of permanence, time and place for future generations. Yes, if you intend to take advantage of federal tax credits. The Rehabilitation Tax Incentive Credit program provides people interested in obtaining the credit three years to complete a nomination and have a property enrolled in the National Register. You can do the work before the property is enrolled and claim the credits. If the property is not enrolled at the end of the time period, the tax credits are revoked and must be repaid to the Internal Revenue Service.