Carpet is commonly made in widths of 12 feet (3.7 m) and 15 feet (4.6 m) in the US, 4 m and 5 m in Europe. Where necessary different widths can be seamed together with a seaming iron and seam tape (formerly it was sewn together) and it is fixed to a floor over a cushioned underlay (pad) using nails, tack strips (known in the UK as gripper rods), adhesives, or occasionally decorative metal stair rods, thus distinguishing it from rugs or mats, which are loose-laid floor coverings. For environmental reasons, the use of wool, natural bindings, natural padding, and formaldehyde-free glues is becoming more common. These options are almost always at a premium cost.
In the UK, some carpets are still manufactured for pubs and clubs in a narrow width of 27 inches (0.69 m) and then sewn to size. Carpeting which covers an entire room area is loosely referred to as 'wall-to-wall', but carpet can be installed over any portion thereof with use of appropriate transition moldings where the carpet meets other types of floor coverings. Carpeting is more than just a single item; it is, in fact, a system comprising the carpet itself, the carpet backing (often made of latex), the cushioning underlay, and a method of installation. Carpet tiles are also available, typically 50 centimetres (20 in) square. These are usually only used in commercial settings and are affixed using a special pressure-sensitive glue, which holds them into place while allowing easy removal (in an office environment, for example) or to allow rearrangement in order to spread wear.
"Carpet binding" is a term used for any material being applied to the edge of a carpet to make a rug. Carpet binding is usually cotton or nylon, but also comes in many other materials such as leather. Non-synthetic binding is frequently used with bamboo, grass and wool rugs, but is often used with carpet made from other materials.