"To erect," "to construct" and "to build" a building, as used in this chapter, include "to alter," "to add to" and "to relocate" a structure of any kind and to excavate or grade a lot in preparation for building a structure thereon or changing the use of the property; and before any such undertaking is commenced, including initiation of construction of infrastructure, including roads, utilities and drainage systems for any approved subdivision or site plan, a building permit therefor is required, except that no such permit shall be required for interior additions to or alterations of a building if the total cost or value of such additions or alterations is less than $1,500 or exterior additions to or alterations of a building if the total cost or value is less than $1,000, provided that such cost or value shall include the value of the labor, no matter by whom performed; and any additions to or alterations of a building to be occupied for the first time as living quarters for a person or any conversion of a one-family dwelling unit to a two-family unit or summer dwelling to a year-round residence shall require a building permit, no matter what the cost or value of such additions, alterations or conversion.