Fiber is the oldest type of carpet cushion. It was originally made from animal hair, a byproduct of the tanning industry. The hairs were pressed into a felt mat, which could be impregnated with rubber. When hair became less available, other materials like jute and recycled textile fibers were used. Today, synthetic fibers like nylon are commonly used to make fiber cushions.
Fiber mats aren't generally used for residential carpet installation, but they can be ideal in certain situations. In homes today, they are mainly laid down under area rugs to prevent their movement. They're more common in commercial situations to provide a very firm foot feel under carpets.
As with any pad, density is key to choosing the right fiber pad. Here are the HUD recommendations:
- Rubberized hair or jute --For light or moderate traffic: 0.27 inch (6.86 millimeters) and 12.3 pounds per cubic foot (197 kilograms per cubic meter). For heavy traffic: 0.375 inch (9.525 millimeters) and 11.1 pounds per cubic foot (177.8 kilograms per cubic meter).
- Synthetic fiber -- For light or moderate traffic: 0.25 inch (6.35 millimeters) and 6.5 pounds per cubic foot (104 kilograms per cubic meter). For heavy traffic: 0.30 inch (7.62 millimeters) and the same weight requirement used for light traffic.
- Recycled textile fiber -- For light or moderate traffic: 0.25 inches and 7.3 pounds per cubic foot (117 kilograms per cubic meter). For heavy traffic: 0.30 inch and the same weight.
Fiber padding has some drawbacks, though. Natural fibers can rot if they get wet, and dampness can be a problem that makes your carpet pad smell bad. Using spun nylon and other synthetic fibers can prevent these issues. You should always go with synthetic-fiber padding if you're using it in a basement or on concrete.
Read on for lots more information about carpet padding.