No building or land shall hereafter be used or occupied and no building or part thereof shall be erected, moved or altered unless in conformity with the regulations herein specified for the zone in which it is located.

No building shall hereafter be erected or altered:

No part of a yard or other space required about any building for the purpose of complying with the provisions of this chapter shall be included as a part of a yard or other open space similarly required for another building.

Where the Zoning Board of Appeals finds that extraordinary hardship may result from strict compliance with these regulations, it may vary the regulations so that substantial justice may be done and the public interest secured, provided that such variation will not have the effect of nullifying the intent and purpose of the Official Zoning Map or these regulations. The foregoing provision does not apply in matters involving variances.

In residential zones, there shall be only one principal use of a lot. In all zones, permitted agricultural uses may be carried on in conjunction with a residential use, but in no event shall a lot contain more than one residential dwelling structure. In nonresidential zones, more than one principal use may occupy a lot or structure upon issuance of a special permit, and site plan review and approval.

Any use not expressly or specifically set forth as a permitted use in any zone shall be prohibited in that zone. A use specifically set forth as a permitted use in one zone shall not be permitted in another zone unless it is expressly and specifically set forth as a permitted use in said other zone.