Make sure you only hire contractors who are certified and licensed to work in your state. Concrete walls have the potential to create significant problems if they are done incorrectly, so they are highly regulated. Contractors pouring concrete walls will generally have to undergo a lot of training to become certified in their work. Your local building inspector should be able to provide you with a list of licenses required for contracting in your state.

Ask to see a portfolio of past work completed by the contractor. Take a look at the quality of the work and see if the quality matches what you're looking for. A poured concrete wall can look terrible if it's not done correctly. It can also be a dangerous thing to live or work around. Pictures of previous work done by the contractor will help you get a better idea of his or her skills.

Find references for the contractor before you hire anyone. References will give you the opportunity to learn a little about the contractor before you hire him or her. This can save you the trouble of hiring an incompetent contractor.