Carpet is commonly made in widths of 12 feet and 15 feet in the USA. Where necessary different widths can be seamed together with a seaming iron and seam tape and it is fixed to a floor over a cushioned pad using nails, tack strips, adhesives, or occasionally decorative metal stair rods. 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, though with no sacrifice to performance.
Carpet tiles are also available, typically 50 centimeters (20 in) square. These are usually only in commercial settings but are growing more common in residential applications and are affixed using a special pressure-sensitive glue or tape, which holds them into place while allowing easy removal (in an office environment, for example) or to allow rearrangement in order to spread wear.