A contractor and homeowner agree to change the scope of work during a project. This agreement must be:

Explanation

B&P §7159(d) requires a home improvement contract and any change to it to be in writing and signed by the parties before the work covered by the change begins, and §7159(c)(5) says a change-order form becomes part of the contract only on those terms. An invoice sent afterwards documents a bill, not an agreement made in advance. The building department reviews code compliance and issues permits; it has no role in making a price change enforceable between owner and contractor. And no section requires change orders to be filed with CSLB, on a 10-day clock or any other.