AUTHORITY OF BOARD.

(a) The board of adjustment may:

(1) hear and decide an appeal that alleges error in an order, requirement, decision, or determination made by an administrative official in the enforcement of this subchapter or an ordinance adopted under this subchapter;

(2) hear and decide special exceptions to the terms of a zoning ordinance when the ordinance requires the board to do so;

(3) authorize in specific cases a variance from the terms of a zoning ordinance if the variance is not contrary to the public interest and, due to special conditions, a literal enforcement of the ordinance would result in unnecessary hardship, and so that the spirit of the ordinance is observed and substantial justice is done; and

(4) hear and decide other matters authorized by an ordinance adopted under this subchapter.

(b) In exercising its authority under Subsection (a)(1), the board may reverse or affirm, in whole or in part, or modify the administrative official's order, requirement, decision, or determination from which an appeal is taken and make the correct order, requirement, decision, or determination, and for that purpose the board has the same authority as the administrative official.

(b-1) In exercising its authority under Subsection (a)(3), the board may consider the following as grounds to determine whether compliance with the ordinance as applied to a structure that is the subject of the appeal would result in unnecessary hardship:

(1) the financial cost of compliance is greater than 50 percent of the appraised value of the structure as shown on the most recent appraisal roll certified to the assessor for the municipality under Section 26.01, Tax Code;

(2) compliance would result in a loss to the lot on which the structure is located of at least 25 percent of the area on which development may physically occur;

(3) compliance would result in the structure not being in compliance with a requirement of a municipal ordinance, building code, or other requirement;

(4) compliance would result in the unreasonable encroachment on an adjacent property or easement; or

(5) the municipality considers the structure to be a nonconforming structure.

(c) The concurring vote of 75 percent of the members of the board is necessary to:

(1) reverse an order, requirement, decision, or determination of an administrative official;

(2) decide in favor of an applicant on a matter on which the board is required to pass under a zoning ordinance; or

(3) authorize a variation from the terms of a zoning ordinance.