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STC Ratings For Walls

When you want or need sound reduction in a specific room, you’ll have to make sure that your walls are up to the task. Unfortunately, it’s not always easy to soundproof a room with standard drywall. You might need to fill your walls with insulation or add acoustic panels to help absorb sound waves. However, neither of these options will do much good with a “new” room or space in your home. That is to say, if you want to close off a space in your home and ensure that little or no sound is getting in or out, you’ll want a retractable wall with a high STC rating.

Finding a wall that’s durable, versatile, budget-friendly, and has a high STC rating doesn’t need to be a challenge. At Tudelü, we offer various models of retractable walls with STC ratings for sound reduction and soundproofing. But if you’re unfamiliar with STC ratings for walls, then you likely have some questions that need to be answered before you start shopping for a partition wall.

For instance, What does STC stand for? How is it calculated? What do different STC ratings really mean? What STC rating do you need for walls? Finally, where can you get the best STC-rated retractable walls on the market?

In today’s guide, we will answer all of these questions and more, so let’s get started!

What Is STC?

STC stands for “Sound Transmission Class.” As the name implies, STC is a rating system that grades different materials based on how sound waves go through them. For example, a low STC rating means that a material does not reduce sound very much; sound waves are able to go through the material easily. Alternatively, a high STC rating means that sound waves are heavily blocked or reduced by a material.

Sound Transmission Class is not a concept that you’ll deal with in your day-to-day life unless you’re an architect, builder, interior designer, or someone who works with STC-rated materials. This is because STC ratings are most often applied to walls, floors, ceilings, doors, and windows. Nonetheless, if you’re planning to put a new wall in your home or you simply want to understand how well your walls are keeping sound out (or in), you’ll need to understand what different STC ratings mean.

STC Ratings

When determining the STC rating, a given material will be assigned a specific number. As previously mentioned, lower numbers mean that more sound can get through, while higher numbers mean that less sound can get through. Here’s a more detailed breakdown of what you can expect from STC ratings that fall within specific ranges:

  • STC 25 to 29 - 25 is the lowest possible STC rating, but anything between 25 and 29 will have very poor sound reduction. Sound will get through the material very easily.
  • STC 30 to 39 - STC ratings between 30 and 39 will offer basic sound reduction. Louder or more persistent sounds will be muffled, but still audible. This is ideal for keeping out the relatively quiet sounds (40 decibels or below) and is most common in standard interior walls (without insulation).
  • STC 40 to 49 - STC ratings between 40 and 49 reflect quality soundproofing. While some very loud noises may still get through, normal conversation (or any sound between 50 and 70 decibels), will not be able to penetrate the material. This rating is common for exterior walls or interior drywall with substantial insulation.
  • STC 50 to 65 - STC ratings of 50 or higher are more common in commercial settings, like hotels or professional sound studios, as well as exterior residential walls. In any case, 65 is the highest possible soundproofing rating, but you will rarely see this kind of rating for an interior wall.

How Is STC Calculated?

STC ratings have to be measured in a lab environment, but as long as the necessary equipment is present, the calculations themselves are quite simple. Essentially, STC is tested by measuring the Sound Transmission Loss (STL) at different frequencies. STL is found by taking the number of decibels recorded on one side of the wall or material (where the sound originated) and the number of decibels recorded on the other side of the wall or material, and then subtracting the second number from the first.

Most testing will measure the STL across 16 standard sound frequencies. This means that the average Sound Transmission Loss can be calculated by adding up all of the STL figures, and dividing them by 16 (or however many frequencies are tested). This will give you the STC rating. Other factors can be considered as well, such as curve corrections to account for nuances in human hearing and how sound behaves in certain environments. These corrections are generally applied to the STL figures prior to the final calculations.

STC Rated Walls

STC-rated walls have been tested using the methods outlined above and given a single number to represent their soundproofing. Here are a few examples:

  • Standard Single-Layer Drywall - STC rating between 30 and 35
  • Stud Wall with Insulation - STC rating between 40 and 45
  • Soundproofing Drywall - STC rating between 45 and 50
  • Concrete Block Wall with Insulation - STC rating between 48 and 55
  • Specialized Acoustic Wall system - STC rating of 50 or above

Naturally, these are just approximations, and a lot of different factors can affect the STC rating of a specific wall. However, as a general rule, the underlying material, thickness, and presence or absence of insulation are some of the most important factors that can raise or lower an STC rating. Choosing the right wall or material to reduce or completely block sound will ultimately come down to your needs and personal preferences. For example, if you just need a quiet place to study in your home, you might want a simple wall with an STC rating between 35 and 40. Alternatively, if you really want to keep noise in or out, you’ll want to upgrade to a wall with an STC rating between 45 and 50.

Tudelü Noise Reducing Walls

Do you want walls that will greatly reduce noise in a specific room or area of your home or business? Are you looking for motorized retractable walls with high STC ratings? Finally, do you want to have fully soundproofed walls to stop sound from getting in or out? If so, Tudelü has what you’re looking for.

Here are all three of our sound-reducing and soundproofing retractable wall models:

  • Private - The Private partition wall has an STC rating of 36. This makes it equivalent to standard drywall, but with the flexibility to raise and lower the wall as needed.
  • Secluded - The Secluded partition wall has an STC rating of 40. This makes it a strong sound barrier that is similar to double-layer drywall with insulation. But once again, you have the flexibility to open or close off an area with just the click of a button.
  • Mute - Lastly, the Mute partition wall is our best soundproofing wall, with an STC rating of 48. This means you can have a moveable wall in your home or business with the same soundproofing power as an insulated concrete block wall.

We hope you enjoyed our guide on STC ratings for walls! Are you looking for a high-quality retractable wall to put in your home or place of business? If so, be sure to reach out to Tudelü today!