Sec. 6-144. - Declaration of nuisance; order to demolish or repair. All buildings which are unfit or dangerous within the terms of section 6-143 are hereby declared to be public nuisances, and shall be repaired or demolished and debris removed from the site as provided in this article. The following criteria shall be used by the better building board in ordering repair or demolition: (1) If the building can be reasonably repaired so that it will no longer exist in violation of the terms of this article or other ordinances of the city, it shall be repaired. (2) In any case where a building is fifty (50) percent damaged or decayed or deteriorated, it shall be demolished; and in all cases where the building cannot be repaired so that it will no longer exist in violation of the terms of this article it shall be demolished. In all cases where a building is a fire hazard existing or erected in violation of the provisions of this article or any ordinance of the city or statute of the state, it shall be demolished.