Restoration and reconstruction by-right. Nothing in this ordinance shall prevent the reconstruction or substantial restoration and the continuance of use of a nonconforming multifamily or nonresidential structure which has been damaged by fire, explosion, flood, riot, act of the public enemy or accident of any kind if the estimated replacement cost of such restorations does not exceed 75% of the most recent appraised building value of the structure as identified on the field record card in effect at the time of the damage that is on record in the West Springfield Assessor's office, provided that the structure as restored shall be constructed within the existing footprint and shall not be greater in volume, height or area than the original nonconforming structure and provided, further, that said restoration is commenced within 12 months of the initial damage and completed within 24 months of said damage. The estimated cost of such restoration shall be determined by the Building Commissioner. If the property owner disputes the determination of the Building Commissioner, he may request that the Building Commissioner base the determination upon receipt of an estimate from an independent contractor selected by the Building Commissioner. The cost to obtain said estimate shall be borne by the owner of the premises and shall be paid to the Town at the time the building permit application is filed. Said restoration costs shall also include all improvements or upgrades required by the State Building Code.