German construction contracts under the VOB/B set strict rules for extra work. A contractor who does work the client demands but the contract does not provide for can claim special payment. Er muss jedoch den Anspruch dem Auftraggeber ankündigen, bevor er mit der Ausführung der Leistung beginnt. But he must announce the claim to the client before he starts the work. For changes the client orders, a new price should be agreed before the work is done. As a rule, work done without an order, or by departing from the order on one’s own, werden nicht vergütet, is not paid. Handling these claims has its own name in the industry: Nachtragsmanagement, the management of contract supplements.