Filinvest Alabang v. Century Iron Works

Summary

Century Iron Works sued Filinvest Alabang for P1,392,088.68 allegedly withheld from construction contract payments. The Supreme Court affirmed the Court of Appeals ruling that Filinvest was estopped from claiming defective workmanship after issuing a completion certificate, and that despite the lump sum nature of the contract, additional work for a scenic elevator enclosure was validly authorized through proper written instructions and cost agreements under Article 1724 of the Civil Code. The decision established that contractors can recover additional costs in lump sum contracts when both written authorization and pricing agreements exist, preventing unjust enrichment of project owners who benefit from extra work.