Construction of a building. Prepare the building site and pour the foundation. Rough framing is finished. Complete the rough plumbing, electrical, and HVAC systems. Install the windows and doors. Finish the interior with flooring and wall coverings. All buildings are constructed in stages. The first stage of construction is called "pre-framing." This term refers to the process of constructing the frame of the building before the roof is installed. The goal of pre-framing is to get all the parts of the frame in place so they can be connected later with screws or nails. The frame is the strong internal structure of the building. It consists of beams, columns, and walls that provide support for the building's floors and ceilings. After the pre-framing stage is complete, the next stage is called "rough carpentry." In this stage, the builders work on the actual house framework, which includes installing door and window openings, creating header and footer details, and adding molding where needed. They also finish the rough plumbing, electrical, and HVAC systems at this time. In this stage, the interior of the building is finished by covering the walls and ceilings with paper-thin sheets of drywall.