If the contractor wants to tear something out that is non-conforming and rebuild it per the approved drawings I do not see why the engineer needs to be asked if it was ok to build it per the approved drawings. The owner and the design professionals should be made aware of the problem so they can more closely monitor the contractor. The owner should try to understand the cause of the problem in part to understand whether the contractor may make a claim to be reimbursed because he believes somebody else was the cause of the problem.