Properties subject to the requirements of this article and designated as the corridor enhancement district include all properties located with 750 feet of the right-of-way of:

1. (1)
   Texas State Highway 105, extending from the eastern boundary of the corporate limits of the city to the western boundary of the corporate limits of the city.

Properties subject to the requirements of this article and designated as the corridor enhancement district include all properties located within 300 feet of the right-of-way of:

1. (1)
   Texas State Farm Road 149, extending from the northern boundary of the corporate limits of the city to the southern boundary of the corporate limits of the city; and
2. (2)
   The entire Lone Star Parkway, extending from Texas State Highway 105 on the east to Texas State Highway 105 on the west; and
3. (3)
   Texas State Farm Road 1097, extending from the northeastern boundary of the corporate limits of the city to Texas State Farm Road 149.

The city council may, from time to time, following recommendation either for or against such designation by the planning and zoning commission, designate certain additional areas in the city as a corridor enhancement district, and define, amend, or eliminate the boundaries of designation. Such designation and the requirements thereof shall be in addition to any other zoning district designation or requirement established in this chapter. All zoning maps shall reflect the corridor enhancement district by the letters "CE" as a suffix to the use designated. Changes to the corridor enhancement district may be initiated by any person by request submitted to the city secretary.

The construction of metal buildings is allowed within the corridor enhancement district; however, metal panels and exposed concrete masonry units (CMU) of any kind are prohibited on the exterior walls and facades of such buildings. Areas zoned as District ID are partially exempt from this requirement, provided that the main entrance of the building visible from the main entryways and corridors shall be 100 percent covered by the approved materials listed in subsection (b) of this section. The remaining exterior facades of a building within an area zoned as district ID must be at least 50 percent covered by a wainscoting of the approved materials listed in subsection (b) of this section, from the front to the back of the façade wall.

Within the corridor enhancement district, acceptable façade materials that may be used on buildings or structures, individually or in combination, include:

1. (1)
   Natural stone.
2. (2)
   Brick.
3. (3)
   Wood.
4. (4)
   Fiber cement siding (e.g., Hardiplank).
5. (5)
   Stucco or similar exterior finishing system.
6. (6)
   Pre-cast concrete panels which are painted or integrally colored.
7. (7)
   Exposed aggregate concrete.
8. (8)
   Any other acceptable system that is not metal panel.

New construction within the corridor enhancement district or buildings moved into the corridor enhancement district will be subject to the construction standards defined in this article.

The city encourages property owners, architects and builders to recognize the historic significance of the city, and the desire to maintain and enhance the historic ambiance of the area. Therefore, voluntary compliance with other architectural aspects of the design guidelines for the city is strongly recommended.

Commercial, institutional, and residential structures existing within the corridor enhancement district, prior to the effective date of the ordinance from which this article is derived, shall not be required to be altered, repaired or modified to meet existing design criteria unless major façade or structural renovations are planned by the property owner. Major façade or structural renovations are defined as changes or renovations to 25 percent or more of any façade of the structure or improvements facing a public right-of-way, street or roadway.

Exceptions to these requirements may be reviewed by the planning and zoning commission for a recommendation to city council for approval on a case-by-case basis, provided that the commission and city council find that the proposed building materials and arrangement of these materials will enhance and preserve the character along the corridor in which the structure is located. Consideration for exceptions to the above requirements shall be based on the architectural design and creativity of the structure, and its compatibility with surrounding developed properties.

Exceptions reviewed by the planning and zoning commission and approved by city council shall be in effect for only the structure specifically authorized and shall become null and void should no building permit be issued within 90 days or should the building permit for the specific structure expire.

The provisions of this article shall not be construed to apply to properties located within any planned development district in which deed restrictions have already been approved by the city.

A list of intended exterior materials will be submitted along with the building permit application. Building permits will not be approved unless acceptable external materials will be used.

The city engineer and/or building inspector will review construction to ensure compliance with this article, and no certificate of occupancy will be granted until compliance with this article is achieved.