CAUCHON, J.
The plaintiff has appealed, pursuant to G.L. c. 40A, §17, a decision of the defendant, Board of Appeals of the Town of Arlington ("Board"), dated January 26, 1987 denying the plaintiff's petition for a special permit for the expansion of a nonconforming structure located at 379-385 Massachusetts Avenue.
A trial was held July 9, 1987 at which a stenographer was sworn to transcribe the testimony. Ten exhibits including a stipulation of facts were filed, which exhibits are incorporated herein for purposes of any appeal. One witness testified.
Pertinent matters contained in the stipulation, Exhibit 1, [Note 1] are:
2. Locus consists of a lot, 28,002 square feet in size, upon which has been erected an apartment building eight stories in height. Pursuant to the zoning by-laws of the Town of-Arlington, locus is zoned "R7".
4. The plaintiff's apartment building was constructed in 1970. In order to secure a permit for the construction of the building, it was necessary for the plaintiff to seek variances from provisions of the by-law relating to maximum lot coverage and to the minimum required landscaped area.
5. One variance was required because the building, as designed, covered more than 30% of the lot area, where 30% coverage was the maximum allowed in the district.
6. A second variance was required, because Johnson proposed to construct balconies, as part of the required landscaped area, which balconies were covered by more than 50% by building walls, where the by-law set a 50% limit upon such coverage.
9. The building on locus was built in accordance with the plans which were incorporated by reference in and made a part of the zoning variance decision. (Exhibit 3)
10. In October of 1975, the Town of Arlington adopted a new zoning by-law, differing in many respects from the bylaw in existence in 1970. The building upon locus failed to conform to the amended by-law in the following respects:
(a) The existing building is 64 feet in height, while the amended Article 6 of the zoning bylaw provides for a maximum building height of 40 feet in the R7 district.
(b) Article 6 further limits the number of stories in a R7 zone to five, and the existing number of stories for the subject structure is eight.
(c) The existing "floor to area ratio" of 2.49 is larger than the 1.5 allowed by the by-law.
(d) The existing amount of lot area per dwelling unit is 400 square feet where 550 is now required.
(e) The building provides less than the required amount of parking per dwelling unit.
11. In September of 1986, Johnson applied to the Zoning Board of Appeals, pursuant to the provisions of G.L. c. 40A, §6, and 9.10 of the Arlington zoning by-law, for permission to construct a residential penthouse on top of the existing apartment structure. The penthouse, as depicted on plans submitted to the Zoning Board of Appeals, copies of which are attached hereto as Exhibit 6, consists of a three bedroom living unit covering 2970 square feet located on the roof of the building.
12. After a hearing, the Zoning Board of Appeals rendered the decision from which the instant appeal is taken. (Exhibit 8)
On appeals such as this, the Court hears the matter de novo, makes its own findings and may not disturb the decision of the authority, here the Board, unless the decision rests on legally untenable grounds or is unreasonable, whimsical, capricious or arbitrary. MacGibbon v. Board of Appeals of Duxbury, 356 Mass. 635 , 639 (1970). The Court may not substitute its judgment for that of the Board. Subaru of New England, Inc. v. Board of Appeals of Canton, 8 Mass. App. Ct. 483 , 486 (1979).
The plaintiff has sought a special permit for the expansion of a nonconforming structure under section 9.10 of the by-law. It is clear from the facts stipulated and exhibits, however, that such expansion would violate at least two sections of the by-law which pertain to the expansion of nonconforming structures, Sections 9.02 (...any resultant alteration shall not cause the structure to violate the dimensional and density regulations...) and 9.04 (No building area or floor area, where already nonconforming, shall be increased so as to be in greater nonconformity). The plaintiff's reliance on c. 40A, §6 as requiring, regardless of the bylaw, only a finding that the expansion shall not be substantially more detrimental to the neighborhood than the existing structure is misplaced. G.L. c. 40A is an enabling act which establishes only minimal standards. It does not prevent the local legislative body from establishing additional criteria for zoning relief, provided such criteria are within the purposes of the act. It is generally accepted that one may not as of right alter a nonconforming structure and indeed absolute prohibition of any change, enlargement or extension of nonconforming uses has been held valid, Sullivan v. Board of Appeals of Harwich, 15 Mass. App. Ct. 286 , 288-289 (1982).
Accordingly, I find that the decision of the Board rests on legally tenable grounds and is not unreasonable, whimsical or arbitrary, and therefore, the decision must be affirmed.
The defendant has argued two additional grounds upon which the Board's decision might be affirmed but in view of the foregoing, these arguments need not be discussed.
Judgment accordingly.
FOOTNOTES
[Note 1] The numbers correspond to the items in the stipulation.