No building erected or hereafter erected shall be moved, altered, added to or enlarged, nor shall any land or building be used, designed or arranged to be used for any purpose other than a purpose which is included among the uses permitted in the district in which such building or land is located, nor conducted in any manner contrary to any of the requirements specified in said district.

No building shall hereafter be erected, reconstructed or structurally altered to exceed in height the limit designated for the district in which such building is located.

No building shall hereafter be erected, nor shall any existing building be structurally altered, enlarged, rebuilt or moved, nor shall any open space contiguous to any building be encroached upon or reduced in any manner, except in conformity with the yard, lot width and area, building location, percentage of lot covered by building area, minimum habitable floor area, off-street parking space, off-street loading space and other applicable space and area regulations designed for the district in which such building or space is located, subject to such modifications thereof and such general provisions as are set forth in said district.

Off-street parking space and off-street loading space shall be provided as specified and shall be provided with necessary passageways and driveways appurtenant thereto and giving access thereto. All such parking space and loading space, together with such passageways and driveways, shall be deemed to be required space on the lot on which the same is situated and shall not thereafter be encroached upon or reduced in any manner except as otherwise provided.

No yard or other open space provided contiguous to any building for the purpose of complying with the provisions of this chapter shall be considered as providing a yard or open space for any other building, and no yard or other open space on one lot shall be considered as providing a yard or open space for a building on any other lot.

Where a lot is formed from part of a lot already occupied by a building, such separation shall be effected in such manner as not to impair any of the requirements of this chapter with respect to the existing buildings and all yards and other open spaces in connection therewith, except as may be otherwise required or provided by law, and no permit shall be issued for the erection of a building on the new lot thus created unless it complies with all of the provisions of this chapter.

In the case of any lot or plot substandard in area or width by the terms of this chapter, the rights acquired or existing therein for the use of said lot or plot as a building parcel shall terminate and become nonexistent and void should said substandard plot merge in fee with any adjoining land or property. Such merger shall be deemed to occur when the same person or persons acquire, obtain or have fee ownership in both parcels, whether by purchase, sale, devise, gift or otherwise.

Nothing in this chapter shall be deemed to require any change in the plans, construction or designated use of any building, the actual construction of which was lawfully commenced prior to the time this chapter or any amendment thereof affecting the same takes effect and on which building actual construction is complete within one year after such time.

For single- and two-family detached dwellings, there shall be only one principal structure per lot. For commercial and industrial uses, there shall be only one principal use per lot, although more than one structure shall be permitted; if there are several lessees or owners occupying separate principal structures, a subdivision shall be required so that there will be only one principal structure per lot.