Sleuthing -

• Contact the Washington Department of Labor and Industries. You can ask them if a particular contractor is registered to do business in Washington State.
• Ask the contractor for proof of insurance. Insurance is usually required by the state and should include a completion bond, disability and worker's compensation insurance. Otherwise, you may be liable for accidents occurring on your property.
• Check on the firm's reputation. Ask the local Better Business Bureau, home builders association, or building trades council. Also ask for, and check, references.

Get it in writing -

• Get a written estimate. You will need to give the contractor a written scope of work. This should include everything you expect the contractor to do. Be sure to be very thorough with your work request and have plans and materials specified.
• Get more than one contractor to give you an estimate for the job. Even with the same work description you will find that every contractor will give you a different price. When comparing estimates look at them closely and be sure each contractor is pricing out the same work and materials.
• Obtain a contract. The contract should be complete and clearly state all the work, costs, and payment schedule. Never sign a blank contract or one with blank spaces. It may be worthwhile to have your attorney look it over if a lot of money is involved.
• Ask for guarantees. Any guarantees from the contractor should be written into the contract. It should include what is guaranteed, who is responsible for the guarantee (dealer, contractor, manufacturer), and the length of time the guarantee is valid.
• Get a final contract. A signed contract is binding on both you and the contractor. Don't sign completion papers or make the final payment until the work is completed to your satisfaction and approved by your local building inspector.

Beware of:

• "Special Deals" offered after a disaster by contractors you don't know.
• Unknown contractors wanting to use your house as a "model home".
• Being asked to pay cash on the spot instead of a check made out to the contracting company. A reasonable down payment is up to 30% of the total project cost.

Additional Points:

• Do not sign any contract under pressure by a salesperson. Federal law requires a three day cooling-off period for unsolicited door-to-door sales of more than $25. If you choose to cancel such a contract within three (3) business days of signing it, send your cancellation by registered mail.
• Your contractor should call you or a qualified observer to inspect hidden work (e.g., sewers or basement walls) before it is covered over. Most building departments must inspect electrical and plumbing lines before the walls are covered with wall board or paneling.