Except as provided in Subsection E hereinafter, any type of nonconforming use of buildings or land may be continued indefinitely, but:

Except as provided in Subsection D hereinafter, no building which houses a nonconforming use shall be:

Any building which houses a nonconforming use and which is damaged or destroyed by less than 50% of its cubical content or sound value exclusive of the foundation, from any cause, may be restored but not enlarged, and the nonconforming use reinstated within six months of such damage; if the restoration of such building is not completed within the said six-month period, the physical operation of the nonconforming use of such building shall be deemed to have ceased, unless such nonconforming use shall have been carried on without interruption in the undamaged portion of such building.

Any building housing a conforming use which does not conform to other than use regulations as set forth in this chapter may be rebuilt if damaged, but shall not be altered or enlarged so as to increase the degree of nonconformity thereof.

Nothing in this article shall be deemed to prevent normal maintenance and repair of any building or the carrying out, upon issuance of a building permit, of major structural alterations or demolitions necessary in the interest of public safety. In granting such a permit, the Building Official shall state the precise reason(s) to the Board of Adjustment why such alterations were deemed necessary.

To avoid undue hardship, nothing in this chapter shall be deemed to require a change in the plans, construction or designated use of any building on which actual construction was lawfully begun prior to the effective date of adoption or amendment of this chapter and upon which actual building construction has been carried on diligently. "Actual construction" is hereby defined to include placing of construction materials in permanent position and fastened in a permanent manner. Where excavation or demolition or removal of an existing building has been substantially begun preparatory to rebuilding, such excavation or demolition or removal shall be deemed to be actual construction, provided that work shall be carried on diligently.

All the foregoing provisions relating to nonconforming uses and buildings shall apply to all nonconforming uses and buildings existing at the time of the adoption of this chapter and to all uses and buildings that become nonconforming by reason of any amendment thereof, but not to any use established or building erected in violation of law, regardless of the time of establishment or erection.

Existing nonconforming conditions, including but not limited to inadequate lot size or yards and excess coverage, may be continued, but the degree of nonconformity may not be increased without the securing of a variance. No building may be constructed on a lot less than the minimum size for its district, even if preexisting, without the securing of a variance.