In residence districts, no building shall exceed 35 feet in height, provided that such height limits may be exceeded by one foot for each foot by which the width of each side yard is increased beyond minimum side yard requirements, up to a maximum of 50 feet. In commercial and industrial districts, no building shall exceed 50 feet in height, provided that such height limits may be exceeded when authorized by the Board of Adjustment. Structures supporting utility facilities are exempted from the provisions of this section.