In Colorado, a painter can file a mechanic's lien when they have supplied labor, materials, or services that enhance the value of a property and have not been compensated for their work. Thirteenth St. Corp. v. A-1 Plumbing & Heating Co., 640 P.2d 1130. If you terminate the painter before the work is completed, the legality of such action, and whether the can file a mechanic's lien, depends on the terms of the contract and whether there is sufficient cause for termination.
Whether your painters have the right to file a mechanic's lien thus depends on the contract and what actually happened in your case. Here, it appears you do have a contract, but one without many terms. Since there are no terms regarding termination, the nonbreaching party has the right to terminate the contract in the event of a material breach. (If there are terms, then the termination provisions in the contract will be strictly enforced.) The question is whether the painter's actions rose to the level of a material breach.
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