As a protection to the public corporation and other subcontractors with potential claims, the principal contractor must file a surety bond in double the value of the claim, which also allows the principal contractor to avoid the imposition of interest on the unpaid sums. See Ewing Concrete LLC v. Rochon Corp. of Iowa, No. 14-1628, 2016 WL 146275, at *1 (Iowa Ct. App. Jan. 13, 2016) ("Rochon personally served Ewing with a thirtyday demand letter under Iowa Code section 573.16, requiring Ewing 'commence action in court, within [thirty] days of service of this letter, to enforce its Iowa Code chapter 573 claim' . . . . Iowa Code section 573.16 and relevant case law interpreting this section provide that if Ewing fails to timely file its petition, its statutory claim is time barred."