What is Pooling?

Pooling, watermarking or shading is an optical illusion created by light reflecting off of carpet fibers and making the carpet look wet or water damaged in certain areas.

The most common appearance is a serpentine border around an area of the carpet that looks “wet”. The area is often more obvious when viewed from a particular direction. Pooling can be found in corridors and oddly configured rooms where foot traffic causes unusual patterns.

What Causes It?

People or pets travelling through small or irregular spaces tend to place their feet on the carpet in an irregular way. It is thought that this odd weight placement weakens the pile and allows the pile to reverse in some areas. The reversed pile reflects light differently than the rest of the carpet, creating the illusion that the carpet is wet.

Air flow and ventilation systems have also been studied as possible cause of this phenomena.

Many studies and inspections have been done to find the source of pooling. After much time and effort by builders and carpet manufacturers around the country, there are still no definite answers.

What is the Cure?

Tests that have been performed have proven that pooling is not a manufacturing defect since it normally reoccurs in the same area after carpet is replaced.

To resolve any flooring issue, the problem must be evaluated by a qualified flooring inspector. If the inspector determines that the problem is pooling and it is not considered a manufacturing or installation defect, the only way to prevent the problem from occurring is to replace the carpet with another type of carpet or flooring.

If the same type of carpet is used (dense low pile carpet is the most commonly affected product) for the replacement the problem typically reoccurs. Loop piles, such as those found in Berber carpet, are not as likely to be affected as plush carpet. Also, patterned carpets can lessen the signs of pooling.

The best option might be to go with another flooring product altogether, such as tile, vinyl, laminate, or hardwood.

The Carpet and Rug Institute has this to say about pooling or “shading”: Shading or Pile Reversal Shading is not a change in color, but a change in pile direction (pile reversal) that sometimes appears randomly in a carpet or rug. If you look at the shaded area in one direction it will appear darker, but from another direction it will appear lighter in color. Solid color, cut-pile carpet may show shading more than patterned styles and textured surfaces. Shading is not considered a manufacturing defect. Pile reversal can also be classified as shading and is sometimes called “watermarking” or “pooling.” This condition is usually permanent and has no known cause and no known remedy.