A change order is a written statement authorizing the contractor to perform additional work, or to add time not included in the original construction contract, and it must be signed by both parties before the additional work begins. At the start of a project the contractor provides an estimate of services and costs, but unforeseen damage or latent defects — such as structural damage behind walls or beneath floors that is only discovered once those areas are exposed — often come up mid-project. A change order functions as an addendum to your original contract and protects both sides by documenting the added scope, cost, and schedule in writing rather than by verbal agreement. Undocumented “extras” are a frequent source of billing disputes, which is why Först Consulting Group treats missing or improper change orders as a specific audit item.