There is more to even a simple floor than meets the eye. Below the surface you will find a network of supports, called joists, as well as a variety of connectors and fasteners, depending on the type of floor. Some floors are built to stand alone, such as with finished hardwood, and have no need of additional covering. Others are constructed from sheets of rough plywood and need to have carpet, vinyl or tile covering applied to give a finished look.
No matter which type of carpet you choose, the installation process is similar. Traditionally, carpet is sold in large rolls and cut to size once situated in the particular room. A layer of padding goes down first; installers take care to unroll it perpendicular to the direction the carpet will eventually go. This padding provides additional cushioning for someone walking across the room, as well as a moderate amount of insulation.
A relatively recent innovation in the carpet industry is installing carpet in large squares over the floor, similar to floor tiles, rather than using a wall-to-wall, unbroken roll of material. As with traditional carpeting, carpet squares serve as a comfortable topping over rougher floor material.
The basic difference between a floor and carpet is that the floor, while it can be built as the finished product, is a structural part of the house meant to be covered with your choice of material, of which carpet is one. A house is not considered complete until the floor is installed; the decision of whether to go on with a carpet installation is optional. Like walls and ceilings, the floor is one of the basic building blocks of a house. Carpet is the finishing touch.