All workmanship and materials shall comply fully with the requirements of the approved plans and specifications. If at any time within one year after the date of the final inspection any defect should appear, which in the opinion of the director is due to inferior materials or workmanship, the contractor shall do whatever is necessary to remedy the defects at no cost to the City. The Department will notify the contractor in writing of the defects and repairs to be made. If the contractor fails to begin repairs within ten days, the Department may cause the defects to be remedied and charge the cost and expense involved to the contractor or contractor's surety. The contractor's surety shall not be relieved until the defects or repairs are corrected and approved and a written release is furnished the surety by the Department.