Nonconforming lots, structures and uses.

A. Any residential lot shown on a plan and/or separately described in a deed duly recorded with the Norfolk County Registry of Deeds before the effective date of this bylaw (October 29, 1956) shall be exempt from the setback, frontage and area requirements of this bylaw with a special permit issued by the Board of Appeals if the following conditions are met:

(1) The lot contains at least 50 feet of frontage, 5,000 square feet of area and is in an R District;
(2) The minimum required setbacks shall be as follows: 25 feet front, 13 feet side, and 13 feet rear, and the lot coverage shall not exceed 30%.
(3) The fact that the lot may have been held in common ownership with adjoining land after its creation as a separate lot shall not prohibit the issuance of the special permit, provided that the lot has not been recombined with any adjoining land in a subsequently recorded plan or deed, or used to satisfy area or frontage requirements of this bylaw for an existing structure; and 
(4) The Board of Appeals shall find that the proposed structure(s) shall be in harmony with the surrounding neighborhood, taking into consideration the size and of any adjacent lots, and the mass and design of the proposed structure(s). This Subsection A is intended to prevent undersized lots in developed areas from falling into disuse, and is intended to expand the protection afforded by MGL c. 40A, § 6, fourth paragraph. The Board of Appeals shall have the discretion to deny the special permit provided for herein if it finds that there is other vacant land adjoining the lot which may be available to make the lot less nonconforming, or that the lot has been used for or incorporated into an existing residential use.

B. Any use or structure that is not a single detached dwelling or double attached dwelling that does not conform to these Zoning Bylaws may be continued if the use or structure was lawfully in existence at the time that it became nonconforming, subject to the following:

(1) Change, extension or alteration. As provided in MGL c. 40A, § 6, such preexisting nonconforming structures or uses may be changed, extended, or altered with a special permit by the Zoning Board of Appeals, 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 to the neighborhood than the existing nonconforming structure or use. Once changed to a conforming use, no structure or land shall be permitted to revert to a nonconforming use.
(2) Restoration. Any legally nonconforming building or structure may be reconstructed if destroyed by fire or other accidental natural cause if reconstructed within a period of two years from the date of the catastrophe, or else such reconstruction must comply with these Zoning Bylaws.
(3) Abandonment. A nonconforming use which has been abandoned and/or discontinued for a period of two years or changed to a conforming use shall not be reestablished, and any future use of the premises shall conform to these Zoning Bylaws.

C. Any single detached dwelling or double attached dwelling that does not conform to these Zoning Bylaws may be continued if the use or structure was lawfully in existence at the time that it became nonconforming, subject to the following:

(1) Change, extension, reconstruction or alteration. As provided in MGL c. 40A, § 6. Such preexisting nonconforming structure or use may be changed, extended, reconstructed or altered with the approval of the Building Commissioner if such change, extension, reconstruction or alteration would not increase the habitable floor area by 25% or more and if the Building Commissioner determines that the nonconforming nature of the structure would not be increased per Subsection C(2) below. Once changed to a conforming use, no structure or land shall be permitted to revert to a nonconforming use.
(2) The following circumstances shall not be deemed to increase the nonconforming nature of the structure:

(a) Insufficient areas: change, extension, reconstruction or alteration of a structure that is located on a lot with insufficient lot area, but that complies with all current dimensional requirements for front, side and rear yard setbacks, lot coverage, and building height and build factor.
(b) Insufficient frontage: change, extension, reconstruction or alteration of a structure that is located on a lot with insufficient frontage, but that complies with all current dimensional requirements for front, side and rear yard setbacks, lot coverage, and building height and build factor.
(c) Yard encroachment: change, extension, reconstruction or alteration of a structure that does not further encroach upon any existing nonconforming front, side or rear yard setbacks, but that complies with all current dimensional requirements for the other front, side and rear setbacks and building height and build factor.
(d) Build factor: change, extension, reconstruction or alteration of a structure that is located on a lot that does not comply with dimensional requirements for build factor but complies with all current dimensional requirements for front, side and rear setbacks, lot coverage and building height.

(3) Restoration. Any legally nonconforming building or structure may be reconstructed if destroyed by fire or other accidental natural cause if reconstructed within a period of two years from the date of the catastrophe, or else such reconstruction must comply with these Zoning Bylaws.
(4) Abandonment. A nonconforming use which has been abandoned and/or discontinued for a period of two years or changed to a conforming use shall not be reestablished, and any future use of the premises shall conform with these Zoning Bylaws.

(1) Shall be relocated within the same lot as is practicable to increase conformity with yard setbacks requirements under these Zoning Bylaws and to mitigate impacts or promote more complementary development with the surrounding neighborhood as found by the Zoning Board of Appeals. Once reconstructed in conformance with any yard setback requirement, such a structure shall thereafter not be changed so as to revert to the previous nonconforming condition. The Zoning Board of Appeals may make a finding that relocation of the structure is not practicable, and therefore consider a proposal to rebuild it within the same footprint of the existing structure; and
(2) Shall only be allowed in a zoning district that currently permits single detached dwellings or double attached dwellings as so indicated under § 390-4.2: Use Regulation Schedule. herein; and 
(3) Shall be considered as to whether the structure possesses particular historical significance within the community. Attention shall be given as to its current state of repair and to whether reasonable efforts were or could be made toward adequately maintaining the structure; and 
(4) May expand its gross floor area, provided the structure conforms or does not increase its nonconformity with minimum yard setback, building height and lot coverage requirements of these bylaws, its gross floor area does not exceed 30% of the non-wetland area of the lot, and there is a finding by the Zoning Board of Appeals that the mass and design of the proposed structure is in harmony with the surrounding neighborhood. 
(5) Notwithstanding the provisions of Subsection C and of Subsection D(4) above, the Board of Appeals may allow, in connection with any special permit issued under Subsection D(4), a reduction in the applicable side yard requirements of up to 75%, provided that the width of the lot at the front yard setback is less than three times the applicable minimum side yard requirement, and if the sum of the side yard setbacks created by the new structure will be equal to or greater than those provided by the existing nonconforming structure.