The regulations and restrictions in these regulations shall not be construed as to require the removal, lowering or other change or alteration of any structure not conforming to the regulations as of the effective date of these regulations or to otherwise interfere with the continuance of a nonconforming use, or to require the change in the construction or intended use of any structure which was under construction or alteration commenced prior to the effective date of these regulations.

Where a nonconforming structure or tree exists in any of the areas regulated by these regulations which may affect aerial navigation, the owner of any such nonconforming structure or tree may be required to allow the owner of the Airport, with the permission of the Commission, to install prescribed markers or lights where necessary to indicate to operators of aircraft in the vicinity of the Airport the presence of such airport obstruction.

If the Commission determines that a nonconforming structure or tree has been abandoned or more than 80% torn down, destroyed, deteriorated or decayed:

Except as provided in these regulations, all applications for permits for replacement, change or repair of nonconforming uses shall be granted. [C.G.S. § 15-93(a)]