In the case of a nonconforming use, no such use nor the structure occupied by the same shall be extended or enlarged, nor shall such structure be reconstructed or altered to an extent exceeding 50% of the current market replacement value of such structure, unless said use is changed to a conforming use and provided that no new nonconformities shall be otherwise created.

In the case of a nonconforming structure or a conforming structure located on a nonconforming lot, such structure and the use occupying the same may be extended or enlarged, and such structure may be reconstructed or altered, provided (1) that no existing nonconformities shall be extended or enlarged; (2) that no new nonconformities shall be otherwise created; and (3) that the use occupying such structure or lot shall be a conforming use. For the purposes of this subsection, the enclosure of an open porch, balcony, deck or similar building appurtenance shall be deemed an enlargement of such building. Further, for the purposes of this subsection, any horizontal or vertical extension of a structure along an existing nonconforming setback line shall be deemed an enlargement of an existing nonconformity.

Notwithstanding the foregoing, on single-family residential properties located in the R-4 zone district or in any nonresidential zone district only, an existing principal building with front and/or rear yard setback lines that are less than the minimum required setback distances for the zone district (notwithstanding Subsection 20-5.4c3), may be vertically and/or horizontally extended, subject to the following conditions: (1) that such front and/or rear setback lines are at least 75% of the required minimum setbacks, provided no front or rear yard setback line shall be reduced to less than 30 feet; (2) that the height of any new addition located within a front yard setback that is less than the required minimum front yard setback for the zone district shall be reduced by 1/2 foot for each one foot setback deficiency; (3) the height of any new addition located within a rear yard setback that is less than the required minimum rear yard setback distance for the zone district shall be reduced 1/4 foot for every foot of reduction of the required rear yard setback (4) if both the front and rear yard setbacks are less than the required minimum for the zone district, the height reduction shall be the greater of the two, but shall not be the total of the two; (5) that there shall be no vertical or horizontal extension of any nonconforming side setback lines; and (6) that no new nonconformities shall otherwise be created.

No nonconforming use or structure shall be extended at the expense of a conforming use or structure.

Nonconforming signs shall be subject to the provisions of Subsection 20-24.1h.