Washington State requires all construction contractors to register with the State Department of Labor & Industries (L&I). Section 18.27.040 of the Revised Code of Washington (RCW) also requires construction contractors to be bonded and insured to protect the public.
If you are unable to resolve serious problems with a contractor, you can file suit against their bond. The Washington State Department of Labor & Industries has general information and a more detailed publication about filing a lawsuit against a contractor's bond.
Washington LawHelp also has some information about filing this type of lawsuit.
Self-help kit from the law library
The law library sells a Start a Contractor's Bond Claim self-help kit with forms and instructions to start a claim against the contractor's bond (it does not cover how to finalize the process). It includes forms for either the homeowner or a subcontractor/supplier who has not been paid to use. Kits can be purchased at the library or online and mailed out.