An appeal of an action of the commission relating to the designation of a historic structure, historic site or historic district, the regulation of construction, reconstruction or exterior alteration or the regulation of demolition may be initiated by filing a petition to appeal, specifying the grounds for such an appeal with the city clerk within thirty (30) days of the date on which the final decision of the commission is made. The city clerk shall file the petition to appeal with the common council. After a public hearing, the common council may reverse or modify the decision of the commission. In modifying or reversing a decision of the commission, the common council shall find that, owing to special conditions, the decision of the commission would cause serious hardship to the property owner or preclude reasonable use of the property. Self-created hardship or expectation of increased economic return shall not be the basis for modifying or reversing a decision of the commission. (1975 Code Ch. 21 § XXXII)