- A current insurance certificate
- A list of professional references
- Job site pictures and locations
- Lien releases upon completion of the job
- A written warranty/guarantee
- A list of professional testimonials or references
Most contractors can produce these items; however, it is up to you to decide if a contractor is competent. You can start by asking more probing questions that will uncover the true core competencies of the firm or in what service or solution they specialize.