Roofing Cost - Version 2.0 Roofing Cost - Make Sure You Understand What A Roofing Cost Bid Includes. When you're in the process of building, you will have to work with contractors to get various bids on part of the building. Electrical and plumbing are two areas where you'll need professional bids. One other important area is that of estimated roofing cost. You will need a roofing contractor to give you a bid on the cost of the roofing material, the installation and the expected life of the roofing material. Unless you have all those factors, you do not have a comprehensive bid for your roofing cost. The owner must work with the roofing contractor to ensure that the roofing material chosen is appropriate for the house and the climate. In addition, the owner has to select a roofing material and color that will blend into the environment. Both of these points must be resolved before the roof can be installed. What we commonly call a roof is the outside "skin" of the roofing structure. The roof itself rests on structural parts in a way that creates integrity and strength in the