When construction reveals a condition materially different from what was known at estimate time — hidden rot, unexpected rock, asbestos, unknown utilities, structural deficiency in existing framing — the correct process is: stop work on the affected scope, document the condition with photographs before any removal or remediation, prepare a written change order describing the condition, the additional scope required, the cost impact, and the schedule impact, and present it to the client before proceeding. The client decides how to respond. What should not happen: the contractor proceeding with additional work and informing the client at billing time. Field condition discoveries are decision points for the client, not licenses for the contractor to spend money without authorization. RainFire Builders has an internal policy: no additional work on a discovered condition before the client has seen the photograph and signed the change order.