A directed change is something that the contractor has been directed to change from the project owner. A constructive change could be several things - either something needs to change because of an unforeseen project condition or something should be changed to make it easier or better for the project.
Example of a directed change would be - the owner doesn't want to finish a lower level to save money - so they would execute a pricing request to see how much money they would actually save. Then would execute an owner directed change order to pull the money out of the budget and hence, change the contractors scope of work.
An example of a constructive change would be - the contractor noticed a discrepancy in the documents that is going to cost him an additional $10000 to fix. The contractor would submit an RFI (request for information) to clarify or request to change the issue. The arch/eng/owner would submit an answer back to contractor. Contractor would then issue a change order request to change the scope of work. The owner would then approve change order.
Main difference between them is where they originate from - owner or contractor.
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