Anyone who lives in a multistory home or apartment building understands how important sound transmission can be. When sharing a living space with roommates, family members, or neighbors, no one wants to hear loud, clomping footsteps or be unable to prevent doing the same one's self.

Sound transmission is measured with three different rating systems, each one defining a different way by which sound is transmitted. Sound absorption of floor coverings may be measured on two of those scales. The third covers room-to-room transmission, more appropriate for walls as opposed to floors. 

Impact Insulation Class (IIC): Measures how well a building floor reduces impact sounds, or how well sound vibrations travel through a floor down to the room below. This is especially important in apartment buildings and multistory homes.

IIC 50 has the least impact sound absorption quality. While this may be appropriate for ground floors, it would be unsatisfactory for most on a higher floor without a great deal of insulation in the area between the floor and the ceiling below. Most stone and tile will fall into this category.

IIC 60 indicates a medium impact sound absorption quality, and encompasses floors such as wood, laminates, and some vinyls.

IIC 65 is a high level of impact sound transmission absorption and includes superior sound reduction materials like carpet and cork.

IIC is greatly influenced by the surfaces and areas under the floor.  The IIC rating can be significantly enhanced by the addition of underlayment, insulation, or by floating the floor. The “loudest” floor is stone or tile laid directly over concrete. The IIC scale does not account for joist noises like squeaking or rattling.

Sound Transmission Class is measured in a laboratory, and tests a material’s ability to reduce sounds like voices, televisions, alarm clocks, and more. To put it simply, STC rates a material’s ability to stop airborne sound, measured in decibels. In the United States STC is primarily used to measure any interior partitions, not only floors, butceilings, doors, windows and exterior wall arrangements.

This chart from Alpine Insulation offers a brief and concise look at STC:

Noise Reduction Coefficient (NRC): Measures the amount of sound energy absorbed upon striking a particular surface.

A room with a high NRC rating would eliminate background noise and echoes to help clarify speech. For example, movie theaters must be constructed to have a high NRC rating. Otherwise, sound waves would bounce off the walls and crash into each other, making individual words impossible to distinguish and wasting your valuable time and ticket money. After all, you didn’t pay $10 for some mediocre popcorn only to miss the whole movie!

Carpet has an NRC rating of .40–.50 and is the most efficient absorptive flooring material.

Vinyl, cork, and rubber have a fairly high NRC rating.

SONIC Pros and Cons of Flooring, Best to Worst

CARPET
PROS	CONS
Number one on all counts.	Least durable.
The exact opposite of a hard, echoing surface.	High maintenance.
Sound waves are effectively absorbed and deflected by both the carpet itself and by the padding underneath it.	Traps dust, allergens, and irritants.
Sound absorption can be enhanced with a thicker pad.	Usually bad for allergy sufferers.
Usually the most cost-efficient option in the short term.

CORK
PROS	CONS
A great choice for sound reduction.	Can be difficult to find.
Doesn’t just dampen sound waves, it actually absorbs them.
Such an effective sound reduction material that it is used on walls to soundproof recording studios.

VINYL
PROS	CONS
A good choice for sound reduction.	You get what you pay for, and quality sound-reducing vinyl flooring can be costly.

LAMINATE
PROS	CONS
Can be a reasonably good choice for sound reduction with the addition of a high quality underlayment.	Footfalls can produce a hollow percussive sound when laminate is installed without underlayment.
Cost effective.	Boards can rub together and squeak.

Hardwood, bamboo, tile, and stone are at the bottom of the scale for sound absorption.

If you’re looking to reduce noise caused by an existing floor, consider mats and area rugs for high traffic areas! Cork mats underneath the rugs will further reduce sound. Lower pile area rugs will trap less dust than their shaggier counterparts, and are a quick and easy way to jazz up a décor scheme.

As with all other home improvement decisions, factoring in sound transmission is a balancing act. What may be a quiet floor in a single-person household may wreak noisy havoc in a home with children, pets, and heavy foot traffic.

Got questions about finding the best floor to fit your room, your home, and your lifestyle? Call our trained customer service representatives at 1-800-804-5251, or click to chat today!

– – – –
David has written and made videos about flooring products and installation since 2011 at Floors To Your Home (.com), where he is also the PPC Manager, a Researcher, a Website & Marketing Strategy Team member, Videographer, Social Strategist, Photographer and all around Resource Jito. In my spare time I shoot and edit video, put together a podcast, explore film history, and mix music (as in ‘play with Beatles multi-tracks’). Connect with  W. David Lichty

 

Follow Team Floors To Your Home on  Facebook