To avoid undue hardship, nothing in this Zoning Ordinance shall be deemed to require a change in the plans, construction, size or designated use of any buildings on which actual construction was lawfully begun prior to the effective date of adoption or amendment of this Zoning Ordinance and upon which actual building construction has been carried out diligently. “Actual construction” is hereby defined to include the placing of construction materials in a permanent position and fastened in a permanent manner. Where demolition or removal of an existing building has been substantially begun preparatory to rebuilding, such demolition or removal shall be deemed to be "actual construction", provided that the work has been carried out diligently. Where this is the case, the Zoning Inspector may require proof in the form of an affidavit or similar document that the original intended use of the building has not been changed. The ground story framework, including structural parts of a second floor, if planned for, shall have been completed within one (1) year and the entire building completed within two (2) years after the effective date of this Zoning Ordinance or new zoning and building certificates will be required verifying compliance with the conditions of this Zoning Ordinance or amendments thereto. Where work has been commenced prior to the effective date of this Zoning Ordinance for which no building certificate was issued, although required at the time, or which is in violation of a previously issued certificate, such violations shall stand and shall be prosecuted. Work for which no building certificate has been issue shall be required to comply with this Zoning Ordinance and its amendments.