" The conclusion is inescapable that the board was obliged to and did condition its approval of the location by requiring that it be "as per plot plan." See Youngs v. Zoning Board of Appeals, 127 Conn. 715, 716, 17 A.2d 513. When the plaintiff's appeal from the granting of the variance was sustained in the trial court, the action of the board in granting the variance was overruled.

The board disregarded this and considered the size of the building a matter which had already been passed upon by the commission as being suitable in view of the allowance of multifamily dwellings in this particular district. It would seem that the board adopted the theory that the town plan commission, having decided the particular district was suitable to be zoned for multifamily dwellings, had already ruled that the requirements outlined in § 28b (3) had been satisfied, and to require it to pass on the question amounted to "an inexplicable contradiction." In ruling as it did on the question of proof, in failing to set out any conditions or safeguards, and in its failure to follow the express mandate of the ordinance, the action of the board is voidable on appeal. Youngs v. Zoning Board of Appeals, 127 Conn. 715, 716. In a special defense the defendants cite two previous decisions of the board permitting multifamily use of the applicant's premises and claim they are res adjudicata to the issue raised in this case since no appeal was taken.