What is the difference between turnkey interior contracts and item-rate contracts?

In a turnkey contract, a single contractor coordinates execution across trades under a consolidated agreement. While this offers single-point accountability, price certainty depends heavily on the agreed scope, detailed material specifications, explicit exclusions, and clear variation clauses. Unforeseen site conditions or design changes will still trigger cost adjustments. In an item-rate contract (frequently structured around a Bill of Quantities), work is billed against measured quantities using predetermined unit rates. This approach offers transparent unit pricing and flexibility for design modifications during construction, but requires joint on-site measurement verification to settle final billing. The choice between the two models depends on whether the client prioritizes single-source management or itemized accounting.