The Chief Building Inspector shall have the discretion to waive this requirement for interior alterations to a one- or two-family dwelling, accessory structures attached to a one- or two-family dwelling, including but not limited to decks, porches, pergolas, and sunrooms, and other Improvements to a one- or two-family dwelling that do not result in an increase in the footprint of the principal structure so long as the Chief Building Inspector, or her/his designee, has verified same in the field during an inspection, and subject to the written concurrence of the Commissioner of Planning, Environment and Land Management.