Hire a licensed contractor. Although there are some exceptions, most residential builders, remodelers, and roofers are required to have a state Contractor license. Contact the Department of Commerce Licensing Division (1-800-657-3978) to verify licensure and to check for any sanctions against a particular contractor.
Contact the builder association in your area. There are 20 local builder associations in Minnesota and the Builders Association of Minnesota BAM will gladly tell you which one to contact. If the contractor you have chosen is a member, the Association will have more specific information. Northern Trends Building & Design belongs to The Arrowhead Builders Association.
Contact the Better Business Bureau. They may be able to tell you if any complaints have been filed against the contractor.
Ask for references. Every contractor will have a list of references. Make a point to contact and ask former customers if they were satisfied with the contractor's work, if they encountered any problems, or if they would change anything. Ask to see homes the contractor has built in your price range.
Ask your contractor. How long have they been in business? Where and under what name? Who are their subcontractors? How long have they worked together? Have they been the subject of any legal action regarding their work?
Before you sign the contract: The contract between you and the contractor must be in writing and include: a summary of the work to be done, a description of materials or a list of standard features included, and the total contract price or how the price will be calculated. The contractor must provide to you, at no cost, a copy of all documents, including proposals, quotations, change orders, and purchase orders when signed. Any changes to the conditions of the agreement should be in writing as well. It's also a good idea to include start and completion dates, even though justifiable delays may happen.
After you hire a contractor: After you hire a contractor, it's a good idea to make sure the contractor has obtained the proper permits. For most projects, the contractor must obtain building or zoning permits before beginning the work. Check with your city or county.
(This information is from the Builders Association of Minnesota)