There is no quick answer. Not knowing more about the contract or terms of agreement between you and the contractor, it is difficult to know whether you have an obligation to pay full price for items that are not complete or unacceptable. Also, it would be important to know in what manner the items are incomplete or unacceptable. In Colorado, a contractor can be deemed to have substantially complied with the terms of a contract and though certain aspects may be completed or repaired, it requires payment by the other party to the contract.
There are very specific requirements when filing a lien, and it is not ideal if a lien gets filed. It sounds like you should sit down with the contractor before it comes to that. I would recommend that you consult with an attorney, depending on the size of the dispute, to discuss the best and most efficient method to reach a resolution. Perhaps that would involve the use of a private mediator who could help reach an agreement with respect to the work yet to be done and when and how much money is still to be paid to the contractor. I would start by searching Lawyers.com for attorneys who specializing homeowners in construction defect and lien matters. Most attorneys would be happy to have an initial conversation with you, at no cost, to help determine the best course of action.
Answered on Oct 23rd, 2012 at 11:18 AM