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How Does Sound Floor Underlayment Work?

By Kim Butler Created: May, 2017 - Modified: May, 2021

If you've ever lain awake in a hotel room, listening to the footsteps of the guests in the room above you, or told your teenager to turn down the music in their bedroom, or wished that your condo neighbor had not taken up Irish Dancing as a hobby, you are someone who needs sound underlayment in their life.

Hardwood and laminate floors, and tile, whether ceramic, plastic, or vinyl, are all great flooring choices, with one small problem. As hard surfaces, they all magnify or amplify sound. Even carpet does a lousy job of deadening sound. If you don't want to hear foot fall or footstep noise between the floor and ceiling assembly, you need a sound barrier. Whether you are installing flooring in your own home, or you are an architect or builder of multi-unit facilities (apartments, hotels, schools, dormitories, hospitals, condominiums, etc.) a sound underlayment increases the comfort and privacy of residents.

Underlayments deaden sound by breaking the transmission path between flooring and ceiling assembly. The ''ceiling assembly'' is the trusses, joists, and subfloor that make up your floor and ceiling. By breaking the transmission path, the material deadens what is known as impact noise - the noise created by a foot or something else, like a cast iron skillet, falling on a surface like your floor. But underlayments also reduce airborne noise transmission. So not only will you hear less 'neighbor noise' but when a you drop a spoon on the floor, the clattering sound won't be heard all the way into the bedroom, waking your sleeping infant or spouse.

As you know, sound is actually moving air vibrations, traveling to our ear, which registers the vibration against our eardrum, and brain translates this to sound. A rubber underlayment absorbs these vibrations, preventing or lessening noise transmission.

The Uniform Building Code already requires hotels and apartment houses meet certain sound transmission codes. This is based on the realization that noise is intrusive to other tenants and residents. In buildings like schools or offices, one tenant or classroom doesn't want to hear noise from another office or classroom. The solution is a thin sound underlayment between the flooring and the subfloor. Most underlayments are made of natural materials - rubber or cork.

Rubber has several advantages. First, most underlayment is made of recycled rubber - car tires to be exact. So you are reusing a natural resource, and this may qualify for LEED points on your building project. Secondly, rubber does not compress. It will hold its structure, even with lots of weight placed on it. Other materials can't do this. The bottom line is rubber is the best sound absorption material.


One top brand of rubber sound underlayment is Silent-Tread, which outperforms its competition in head-to-head field testing for noise reduction. It had three times the sound dampening weight of competing products. It actually exceeds the national building code and property association sound reduction requirements. Silent-Tread is also crush proof, meaning it will not be degraded by the flooring resting on top of it. Because Silent-Tread is permanently resilient, it will retain its noise reduction capability for the life of the floor.

Many underlayments can also add thermal value and moisture protection to your floor. Silent Tread is available both with and without a vapor barrier. Silent-Tread XL has a laminated polypropylene film that prevents flooring damage due to vapor transmission through a concrete sub floor.

Another plus of Silent-Tread is that it prevents mold and mildew. The rubber incorporates an EPA registered anti-microbial ingredient called Sani-Shield, to prevent the harmful growth of mold, mildew, algae, and bacteria in accordance with nationally recognized standards. This is especially important when using on a concrete slab or a damp area like a basement.

The product is available in several thicknesses including 5/64 inch, 1/8 inch, 3/8 inch and 1/2 inch in 4 feet widths on 25-foot rolls.

Silent-Tread is also easy to install. Superior density allows the product to lay flat during installation. You can dry lay or glue down. The product be used in new construction or retrofitted into an existing renovation or floor replacement. Finally, Silent-Tread is covered by a industry leading 20 year warranty.

Silent-Tread is available at Their knowledgeable customer service representatives will help you select the product that is right for your application. You can sit back, knowing that you've installed a product designed to perform for years to come.