Increased requirements respecting lot area, frontage, width, yard and similar dimensions provided in this bylaw or amendments thereto, shall be subject to the exceptions provided in MGL c. 40A, § 6 and shall not apply to a lot for single- and two-family residential use which at the time of the recording or endorsement, whichever occurs sooner, was not held in common ownership with adjoining land, conformed to the then-existing requirements and had less than the proposed requirement but had at least 5,000 square feet of area and 50 feet of frontage.
A. 
A nonconforming building or structure, or a nonconforming use of a building, structure or land, which has been abandoned, or which has not been used for more than a period of two years shall not be resumed, provided that where the nonconforming use is agriculture, horticulture or floriculture, non-use shall not constitute abandonment under this bylaw, and the nonconforming use may otherwise be resumed, unless such non-use was maintained for a period of more than five years.
B. 
Voluntary demolition of a nonconforming structure without permission of the Zoning Board of Appeals shall constitute abandonment.
A. 
A lawfully nonconforming use of a building, structure, or land shall not be altered, extended, changed or substantially extended, except to a conforming use, unless authorized by the Board of Appeals pursuant to Subsection B.
(1) 
Alterations to a legally nonconforming use that: a) do not reflect the nature and purpose of the original use; or b) result in a use different in quality, character, or degree from the original use and not ordinarily and reasonably adapted to the original use; or c) result in a use that is different in kind in its effect on the neighborhood than the original use shall constitute a change or substantial extension of the original use.
(2) 
A nonconforming use has been substantially extended if the total of all floor area plus open ground area devoted to such use on the premises has been increased by more than 50% over the total so devoted at the time the use first became nonconforming. This section shall not apply to residential use of single- and two-family structures.
B. 
No nonconforming use shall be extended, altered, or changed unless approved via a special permit issued by the Zoning Board of Appeals upon its finding that such extension, alteration or change will not be substantially more detrimental than the existing nonconforming use to the neighborhood.
A. 
Except as provided in Subsection B, a lawfully nonconforming building or structure shall not be reconstructed, extended or altered except pursuant to special permit issued by the Zoning Board of Appeals upon its finding that such reconstruction, extension or alteration will not be substantially more detrimental than the existing nonconforming structure to the neighborhood.
(1) 
Any reconstruction, extension or alteration of a nonconforming structure that increases an existing nonconformity or results in the creation of an additional nonconformity shall require a special permit from the Zoning Board of Appeals in addition to the finding set forth in Subsection A above.
B. 
Reconstruction, extension, alteration or structural change to a single- or two-family residential, nonconforming structure may be allowed, upon a determination provided that such reconstruction, extension, alteration, or structural change meets all current zoning requirements, is not more substantially detrimental to the neighborhood, and does not increase the nonconforming nature of the structure.
(1) 
Notwithstanding Subsection B above, reconstruction, extension, alteration or structural change (collectively "alteration") of a single- or two-family residential, lawfully nonconforming structure shall be deemed not to increase the nonconforming nature of said structure and shall be eligible for a building permit without review by the Zoning Board of Appeals, if:
(a) 
The structure is located on a conforming lot and the proposed alteration will comply in all respects with the bylaw; or
(b) 
The structure is located on a lawfully nonconforming lot and the proposed alteration will not result in new or increased violation of any of the dimensional requirements of this bylaw.
C. 
No reconstruction, extension, or alteration to a nonconforming structure shall be permitted that results in lot coverage greater than 30%, except for determination by the Zoning Board of Appeals.
D. 
No conforming building or structure devoted to a nonconforming use (whether in whole or in part) shall be moved, reconstructed, replaced or substantially altered, except as authorized by a finding of the Zoning Board of Appeals, pursuant to Subsection A.
E. 
A building or structure devoted to a nonconforming use (whether in whole or in part) and a building or structure nonconforming as to height, setback or yards may, if damaged or destroyed by fire or other accidental cause, be repaired or reconstructed within the same portion of the lot, to the same or lesser dimensions, and used as before, without a finding as provided in either Subsection A or B, provided that such repair or reconstruction is substantially completed within two years of said damage or destruction; otherwise, such building shall be repaired, reconstructed and used only in conformity with the provisions of this bylaw. The Board of Appeals may, however, in a specific case, authorize the extension of the two-year time limit or authorize a special exception from the requirement of conformity, where, in the opinion of the Board of Appeals, such limit or requirement will impose undue hardship.