The Board may reverse or affirm, wholly or in part, or may modify any order, requirement, decision or determination appealed from and shall make such order, requirement, decision or determination as in its opinion ought to be made in the premises and to that end shall have all the powers of the administrative officer. The concurring vote of four members of the Board shall be necessary to reverse any order, requirement, decision or determination appealed from or to decide in favor of the applicant on any matter on which it is required to pass or to effect any variation in the requirements of this chapter.