Most jobs in the construction and contracting business require workers to have certifications or licensing. Some workers benefit from apprenticeships and attaining a two-year technical degree from a trade school. Here are some common kind of certifications to think about obtaining if you are interested in construction and contracting. Plumbing Certification - In order to be a certified plumber, it is best to first become a plumber's apprentice. A registered plumber's apprentice with at least 4,000 work hours are eligible to test and qualify for a tradesman license.