Except in accordance with the provisions of this title, the regulations set by this title within each district shall be minimum regulations and shall apply uniformly to each class or kind of structure or land, including the following:
(1) No building or other structure shall hereafter be erected or altered:
(a) To exceed the height;
(b) To accommodate or house a greater number of families;
(c) To occupy a greater percentage of lot area;
(d) To have narrower or smaller rear yards, front yards, side yards, or other open spaces; than herein required; or in any other manner contrary to the provisions of this title;
(2) No yard or lot existing at the time of passage of this title shall be reduced in dimension or area below the minimum requirements set forth herein. Yards or lots created after the effective date of this title shall meet at least the minimum requirements established by this title;
(3) Where a district boundary line divides a lot in a single or joint ownership of record at the time such line is adopted, the regulations for the less restricted portion of such lot shall extend not more than 30 feet into the more restricted portion, provided the lot has frontage on a street in the less restricted district.