[Amended 5-5-1997 ATM by Art. 40]
Except as hereinafter provided, this chapter shall not apply to uses, buildings or structures lawfully in existence or lawfully begun or to a building or special permit issued before the first publication of notice of the public hearing on this chapter required by MGL c. 40A, § 5, as amended, but shall apply to any change or substantial extension of such use, to a building or special permit issued after the first notice of said public hearing, to any reconstruction, extension or structural change of such structure and to any alteration of a structure begun after the first notice of said public hearing to provide for its use for a substantially different purpose or for the same purpose in a substantially different manner or to a substantially greater extent, except where alteration, reconstruction, extension or structural change to a single- or two-family residential structure does not increase the nonconforming nature of said structure.
A.
Preexisting single- and/or two-family residential structures may be reconstructed, changed, extended or altered without the necessity of a public hearing, provided that it is determined that no such reconstruction, change, extension or alteration shall increase the nonconforming nature of said structure. Such determination shall be made by the Board of Appeals or the Zoning Administrator. In the event that such reconstruction, change, extension or alteration increases the nonconformity of said structure, no such reconstruction, change, extension or alteration shall be permitted unless there is a finding by the Board of Appeals pursuant to a public hearing that such reconstruction, change, extension or alteration shall not be substantially more detrimental than the existing nonconformity to the neighborhood.
B.
Preexisting nonconforming buildings, structures or uses (with the exception of single- or two-family structures) may be changed, extended or altered, provided that no such change, extension or alteration shall be permitted unless there is a finding by the Board of Appeals that such change, extension or alteration shall not be substantially more detrimental than the existing nonconforming use to the neighborhood.
C.
This article shall not apply to billboards, signs and other advertising devices subject to the provisions of MGL c. 93, §§ 29 through 33, inclusive, and MGL c. 93D.