If you decide to use the services of a contractor, take care to choose one with a reputation for honesty and good workmanship. There are several ways to check on a contractor, according to the U.S. Department of Housing and Urban Development:
Consult your local chamber of commerce, the Better Business Bureau, your state attorney general, or your local consumer protection agency.
Talk with people for whom the contractor has done work.
Ask your lender about him, if you plan to finance the project with a loan.
Check his place of business to see that he is not a fly-by-night operator.
Find out, if you can, how he rates with known building-product distributors and wholesale suppliers.
Ask friends and relatives for names of firms they could recommend.
Understand what you sign. The contract both you and the contractor sign should state clearly the type and extent of improvements to be made and the materials to be used. Before you sign a contract, get the contractor to spell out the following in exact terms:
How much the entire job will cost you
How much interest you will pay on his loan (if you choose to use his financing)
How much you will pay in service charges
How many payments you must make to pay off the loan, and how much each of those payments will be
After the entire job is finished in the manner set forth in your contract, you sign a completion certificate. By signing this paper, you certify that you approve the work and materials, and you authorize the lender to pay the contractor the money you borrowed.