(1) In due time prior to commencing the execution of the work owed, the contractor is obliged to prepare those planning documents and to surrender them to the consumer that the latter requires in order to be able to provide proof to the authorities that the work will be executed in compliance with the relevant provisions of public law. The obligation does not exist inasmuch as the consumer or an agent commissioned by the consumer prepares the essential planning requirements.
(2) At the latest upon completion of the work, the contractor is to prepare those documents and to surrender them to the consumer that the latter requires in order to be able to provide proof to the authorities that the work has been executed in compliance with the relevant provisions of public law.
(3) Subsections (1) and (2) apply accordingly if a third party, such as a lender, demands proof of certain conditions being complied with and if the contractor has created the legitimate expectation with the consumer that it is complying with these conditions.