Carpet Pad: Determining the Necessary Thickness

A room with carpet.

Carpet pad comes in a variety of styles that differ in terms of material, thickness, and density. Padding is used to provide cushion and support for carpeting, and is a necessity in almost all installations. Depending on the type of room and how it is used, the right carpet padding is a vital component, providing comfort while helping to increase the life of the carpeting. Residential carpet padding is first categorized according to class.

Class I padding is suitable for low-traffic areas, while class II padding can be installed in either low- or high-traffic areas. It's important not to choose carpet padding based on how comfortable it feels. Instead, the right padding is determined by appropriate thickness, weight and the carpet manufacturer's guidelines.

Carpet Padding Thickness

Besides providing cushion when walking upon carpeting, the padding underneath supports the carpet and helps to increase its lifespan. Padding also contributes to warmth and noise reduction in a room. Padding is available in several materials with a thickness ranging from 1/4 inch to 9/16 inch. The right thickness for a given room largely depends on the traffic and the type of carpet that is installed. Padding should not be too thick in rooms that get a lot of use. Thick padding can impair the carpet from properly stretching upon installation. This can be exacerbated by a lot of foot traffic, which in turn can cause the carpet to form ripples.

Pad Density or Weight

An equally important consideration is the density or weight of the carpet padding. Rated in pounds, 5-pound to 8-pound carpet padding are by far the most common weights used in homes. Carpet padding derives its rating based on the scale weight of 1 cubic foot. Even if carpet padding is thick, if it is not sufficiently dense, the padding can break down faster which helps speed up the breakdown of carpeting.

Combining the Factors of Thickness and Weight

An optimal combination of carpet padding thickness and density will deliver the best, longest-lasting results. In high-traffic areas such as hallways, rec rooms, or stairways, carpet padding should be no thicker than 3/8 inch yet on the denser side. Thinner padding helps prevent the carpet backing from falling apart, while the high density provides comfort and stability. Thicker, more cushioned padding is best in bedrooms and other lower-traffic areas.

Pad Material

Another factor to consider with carpet padding purchase is the material. Carpet padding may be foam or sponge rubber, urethane, or rubberized or latex felt. Urethane and rubber padding are superior to felt in terms of overall resilience, resistance to moisture absorption, flammability, and hypoallergenic design, hence they are the most commonly used types.

Special Considerations

It's important to install padding that matches the carpeting in quality. Inexpensive padding will accelerate the decline of the carpet. Plus, if the carpeting has a warranty, adhering to the manufacturer's guidelines is necessary, or else it could be voided. Specialty installations such as carpeting over a radiant floor heater call for thinner, lower-density padding. Padding installed to improve heat retention or sound absorption should be as thick and dense as possible without exceeding the manufacturer's recommendations.