A contractor is a business that agrees to complete a construction project. Several types of contractors exist, and subcontractors are usually responsible for parts of a larger job. Roofers, framers and flooring installers are usually subcontractors. General contractors are another type of specialized business that works with home and commercial construction projects. These businesses usually handle entire projects and collect bids for certain parts of the job from subcontractors. As an example, you are thinking of building your own home and have found the perfect location. You know nothing of building and need a professional to handle the job. You find the right style of home in a great magazine and order a set of blueprints. You take the blueprints to a number of builders to get an idea of how much money you need. One particular contractor, or builder, agrees to construct and finish your home for $100,000. You sign a contract to seal the deal.