Foam carpet padding can help soundproof a room by providing your carpet with some extra cushion. Even with proper installation, however, there's a risk that the foam carpet padding could make just as much noise as it deadens. The cause of noise from the padding can not only be a defect in the product itself, but also a symptom of a larger problem in your flooring.
Hard Pieces in Foam
Foam carpet padding composed of several different foam particles, including rebond pads, may have hard pieces dispersed randomly throughout the padding. These hard particles are the result of overheating during the foam creation process. According to LGM and Associates, a floor-covering consultation company, hard pieces within rebond pads can produce squeaking sounds when walking on the carpet. Foam carpet padding can also produce crunching noises when multiple hard pieces rub together. Remedying the situation requires you to remove the noisy pads in favor of foam padding without production defects.
Old Floor Construction
If you live in an older home, the noise you're hearing from your floor when you walk may not be from foam padding. The floorboards in a room may have loosened slightly and the subfloor is moving against the wood joists below. This results in the floorboards squeaking. Foam carpet padding may aggravate the problem because it increases the weight on the floorboards and therefore the force with which the boards strike the joists.
Foam Padding Membranes
The waterproof membrane surrounding foam carpet padding can make a crinkling or wrinkling noise as the casing shifts when you and your family members walk on the carpet. This isn't the result of any structural defect or abnormality in the foam carpet padding. Improper installation of the padding can cause unevenness in the casing membrane, which leads to the crinkling noise. Stopping the noise requires you to lift up the top layer of carpet and smooth out the membrane to ensure the covering is flush with the foam padding itself.
Weak Foam Rubber
Foam rubber padding may prove too weak for high traffic areas of your home. According to the International Standards & Training Alliance, foam rubber, including waffle rubber, loses too much density over time to be suitable for areas of your home with heavy foot traffic. When the foam breaks down, the sound it produces is from the flattened rubber bouncing against the underside of your carpet. This can damage the bottom of your carpet if you don't replace the foam padding with a sturdier, more durable alternative.