What Is the Blue Plastic on Carpet Padding?

Identification

• The blue plastic on carpet padding is a moisture barrier, also known as a vapor barrier, designed to prevent moisture from seeping into the pad. Carpet pads may have a moisture barrier on the top side of the carpet pad or on both the top and bottom, depending on the manufacturer.

Benefits

• The blue plastic moisture barrier on a carpet pad keeps spilled liquids in the carpet, rather than allowing them to seep into the pad, and simplifies cleaning. Families with small children or pets may find these pads particularly appealing. Double-sided moisture barriers not only contain spills, but also prevent moisture from concrete slabs or subfloors from seeping into the carpet and carpet pad.

Considerations

• Carpet pads with blue moisture barriers may seem like an ideal solution for basement areas, but because the plastic doesn't breathe, moisture may become trapped under the pad, providing ideal conditions for mold growth. Although the mold may not grow into the carpet, it can still create conditions that contribute to allergies and other health problems. Carpets with moisture barriers typically cost more, as well.

Solutions

• Talk with a flooring expert to determine if a carpet pad with a moisture barrier is the right choice for your floor. Some carpets, such as Berber carpet, require a specific type of carpet pad, and selecting the wrong carpet pad can void your warranty. The location of the carpet and the amount of foot traffic it receives also play a role in determining the carpet pad you should use. In general, a firm, heavyweight carpet pad costs more, but lasts longer and can extend the life of your carpet.