This bylaw shall not apply to structures or uses lawfully in existence or lawfully begun, or to a building or special permit issued before the first publication of notice of the public hearing required by MGL c. 40A, § 5 at which this bylaw or any relevant part thereof was adopted. Such prior, lawfully existing nonconforming uses and structures may continue, provided that no modification of the use or structure is accomplished except as authorized hereunder.

Construction or operations under a building or special permit shall conform to any subsequent amendment of this bylaw unless the use or construction is commenced within a period of not more than 12 months after the issuance of the permit and, in cases involving construction, unless construction is continued through to completion as continuously and expeditiously as is reasonable.

In accordance with MGL c. 40A, § 6, the Building Commissioner may issue a building permit to allow an alteration, reconstruction, extension, or structural change to a lawfully preexisting nonconforming single-family or two-family dwelling, provided that the alteration, reconstruction, extension, or structural change meets the following criteria:

Except as provided in Subsection C below, any proposal to demolish and reconstruct a nonconforming single-family or two-family dwelling shall require a special permit from the Board of Appeals.

For any proposed alteration, reconstruction, extension or structural change other than as provided under Subsection A above, application shall be made to the Board of Appeals for a determination whether such alteration, reconstruction, extension, or structural change will increase the nonconforming nature of said structure. If the Board of Appeals finds that such alteration, reconstruction, extension, or structural change will not increase the nonconforming nature of said structure, the property owner may apply for a building permit and no special permit will be required. In the event that the Board of Appeals determines that such alteration, reconstruction, extension, or structural change will increase the nonconforming nature of said structure, the Board of Appeals may grant a special permit only if it determines that the proposed modification(s) will not be substantially more detrimental than the existing nonconforming structure to the neighborhood.

The Board of Appeals may grant a special permit to change a nonconforming use in accordance with this section only if it determines that such change will not be substantially more detrimental than the existing nonconforming use to the neighborhood, and in making such determination the Board of Appeals shall consider whether the proposed use is different in character or in its effect on the neighborhood or on property in the vicinity.

The Board of Appeals may grant a special permit to reconstruct, extend, alter, or change a nonconforming structure only if it determines that such reconstruction, extension, alteration, or change shall not be substantially more detrimental than the existing nonconforming structure to the neighborhood, and in making such determination the Board of Appeals shall consider whether the proposed structure is different in character or in its effect on the neighborhood or on property in the vicinity.

Reconstruction shall commence within two years after such catastrophe, except that the Board of Appeals may grant an extension of time where strict adherence to this § 320-7.6 would cause undue hardship or because construction has not commenced within two years due to circumstances beyond the applicant's control.

Building(s) as reconstructed shall be located on the same footprint as the original nonconforming structure, and shall be only as great in volume or area as the original nonconforming structure.

In the event that the proposed reconstruction would cause the structure to 1) exceed the volume or area of the original nonconforming structure or 2) be located other than on the original footprint, a special permit shall be required from the Board of Appeals.