Are These the Best R-Values for Soundproofing?

Q: Is R11 or R13 Better for Sound?

R11 is better for sound. It reduces noise in a 2x4 wall more than any other fiberglass insulation product. R11 materials for standard interior steel stud insulation with wall cavities appear in pre-cut lengths—the steel stud walls of R11 help control unwanted noise.

Q: What Is the R-Value of 2x4 Walls?

The R-value for 2x4 walls is either R15 or R13. Many walls have 2x4 studs. On the other hand, there are modern walls half an inch smaller. In these cases, you can use the relatively thin R13 soundproofing material.

R-value seems like it matters more for insulation than soundproofing. However, there is some correlation between a material’s R-value and its ability to mitigate unwanted noise. Ultimately, the best R-value for soundproofing depends on your needs.

The best R-value for soundproofing is R49, which works best for places like ceilings and attics. Other R-values you can consider for soundproofing include R38, R30, R21, R15, and R13. Each of these works best for different purposes.

This article will cover the R-values that work best for soundproofing. I’ll also discuss what to consider when selecting R-values for soundproofing and answer any other questions you may have about soundproofing and R-values.

Also read: Best Insulation Materials for Soundproofing And Acoustics

The Best R-Values for Soundproofing

Not all R-values are created equal. Before you pick the best R-value for soundproofing a specific area for a particular purpose, check their respective pros and cons first. Many R-values are available, and I’ll explain the most common ones below.

R49

R49 is the best insulator for thermal regulation and soundproofing. You can usually find it in attic spaces and ceilings. The insulation material is 16.25 inches (41.28 cm) thick, improving its ability to insulate your home.

Furthermore, R49 is a flexible fiberglass material that absorbs noise and regulates the moisture in places like joists and studs.

Other benefits of R49 soundproofing are:

A utility knife can trim and fabricate the material into your desired shape.
It’s non-corrosive, meaning it won’t harm copper, aluminum, and steel.
It’s dimensionally stable and will not slump or decay when installed.
It’s easy to install, even for beginners.

To insulate using R49, you need seven to eight inches (17.78 to 20.32 cm) of closed-cell foam depending on the material you’re using, and 12 to 13 inches (30.48 to 33.02 cm) open-cell.

R38

Like R49, R38 is a common insulator for attics and ceilings. It’s strong enough to retain heat and minimize damage to your roof. It’s about 12.75 inches (32.39 cm) thick, suitable for insulation and soundproofing.

This insulator is energy-efficient because of its higher R-value, and its soundproofing abilities are top-notch. Also, it’s easy to install and cost-effective. What more could you ask for from a soundproofing material?

R30

R30 is another suitable soundproofing material for ceilings and attic spaces. It’s usually about 10.25 inches (26.04 cm) thick, though you can find various thicknesses depending on the type of material you use for insulation. R30 helps with sound absorption to eliminate unwanted noise.

R30 can cut conductive heat loss from your home by 97%, saving you energy bills. What’s more, its design fits well in cavities sized 2×10. However, you cannot use it for a 2×4 wall due to its thickness.

R21

Although R21’s density is higher compared to R19’s, it’s somehow narrower than the latter. R21 comes in rolls, and you can use it to insulate your 2×6 walls. The insulation material facilitates soundproofing and is an efficient thermal regulator.

R15

You can buy this soundproofing insulation material faced or unfaced. Faced insulators have a barrier on their head, while unfaced ones are best to use on top of existing insulators. R15 works best with 2×4 walls and is also a decent thermal regulator.

R15 has additional variants depending on its ability to reduce noise. Its spray cuts down indoor and outdoor sounds and does a decent job of reducing outside noise.

R13

R13 material resembles a large blanket. It can fill a floor, wall, or ceiling cavity. The R13’s design works best with well-sized modern homes. Whether you’re building a new house or remodeling the existing one, there are a few reasons you should choose R13 batt insulation.

R13 fits 2×4 wall cavities
Its installation is easy, requiring only staples to insulate your wall.
The insulator’s Noise Reduction Coefficient (NRC) absorbs 90% sound.
The batt insulation controls moisture.
R13 requires minimal preparation.
It’s easy to prepare before installation.
It has an R-value of up to 3.8 per inch.

To properly install your R13 Batt, you’ll need the following:

Insulation knife
Stapler
Scissors
Measuring tape
Insulation wires

When installing an R13 insulator, ensure it reaches all sides of the cavity you’re insulating. A regular stapler can secure the wool insulation in place. You can safely use an insulation knife or scissors to remove the insulation.

The good thing about the R13 Batt is you can easily twist it to get a perfect fit. Other than batts, you’ll want airtight exterior walls. You can get these from places with your ideal window frames, door frame switches, and outlets.

R11

R11 works best for controlling sound from the outside. You can buy this insulation material in pre-cut sizes that allow them to fit a wide range of standard wall cavities. The wall insulation for 2×4 framing is 15 pieces per bag, and the installation is usually 15×40 long and 24×86 wide.

R11’s unfaced design makes it ideal for thermal protection. However, it would help if you had friction to fit it between studs, and it may need a vapor barrier that makes it unsuitable for high-traffic areas.

Overall, R11 does an excellent job with soundproofing. The unfaced batts are formaldehyde-free fiberglass for sound control. However, R11 doesn’t work well with exterior walls.

What To Consider When Selecting the Best R-Value for Soundproofing at Your Home

Reading through the R-values listed so far, you’d think they all work for any soundproofing need. However, the best soundproofing value for your home depends on several factors. I have listed some of the most important ones below, with a brief explanation for each.

The Size and Location of the Space You Want To Soundproof

The bigger the location you want to soundproof, the more coverage your soundproof material should offer. Also, consider where you’re going to install your soundproof material. For example, if it’s in a relatively narrow area, pick an R-value that uses the thinnest material possible.

Some soundproofing R-values suit specific environments more than others. For example, places next to construction sites will require a more robust soundproofing material than those in quiet environments. You may also want to install the soundproofing material temporarily.

The Type of Soundproofing Material

Not all soundproofing materials work the same way. Some can cancel out noise entirely, while others will only muffle the sound. You should also check whether the material you want to buy is eco-friendly, especially if you’re keeping it for a relatively long time.

Your Local Regulations on Soundproofing Homes

Some areas have restrictions on soundproofing materials for residential properties. For example, your state may impose a specific fire-resistance value on the soundproofing material homeowners use. If you’re unsure which ones apply in your area, check with your local government.

Your Budget

Of course, you should also factor in your ability to pay for any soundproofing material regardless of its R-value. Generally, materials with high R-values are more expensive than those with lower R-values. It’s worth noting that there isn’t much cost difference between insulators like R15 and R11.

Frequently Asked Questions

I’m sure there’s much more you want to know about R-values and their role in soundproofing your home. Since I cannot fit most of those in the rest of the article, I’ll tackle the most common questions below. If there’s anything I haven’t covered, let me know in the comments!

Does R-Value Matter for Soundproofing?

R-value matters for soundproofing since the primary purpose of installing insulation materials is to insulate your home and decrease sound penetration through the walls. The insulated material traps excess sound from outside, reducing noise.
The best R-value prevents air and sound from moving through the walls. Since noise comes in the form of a wavelength, an R-value that can reduce that wavelength can cut noise by extension.

Is R13 Good for Soundproofing?

R13 is good for soundproofing. Any material with an R13 value works well when absorbing sound traveling through the air. For best results, use R13 soundproofing materials on 2×4 walls and narrow spaces in your home.

Is R11 or R13 Better for Sound?

R11 is better for sound. It reduces noise in a 2×4 wall more than any other fiberglass insulation product. R11 materials for standard interior steel stud insulation with wall cavities appear in pre-cut lengths—the steel stud walls of R11 help control unwanted noise.

Is R13 Better Than R15?

R13 is better than R15 when it comes to soundproofing. If you’re soundproofing narrow spaces, R13 is better since it’s thinner than R15. However, in the case of insulation efficiency, R15 is better than R13 due to its greater R-values.

What Is the R-Value of 2×4 Walls?

The R-value for 2×4 walls is either R15 or R13. Many walls have 2×4 studs. On the other hand, there are modern walls half an inch smaller. In these cases, you can use the relatively thin R13 soundproofing material.

Is a Higher R-Value Better for Soundproofing?

A higher R-value isn’t better for soundproofing. Instead, a higher R-value indicates a material’s ability to insulate or retain heat during the cold months. However, you can augment your existing insulation with materials that work better for soundproofing.

Which Insulation Is Best for Soundproofing?

Fiberglass insulation works best for soundproofing. It’s also fire-resistant, making it easier to comply with local regulations regarding soundproofing material in your area. You can also use polyurethane foam spray as an alternative.

Final Thoughts

The R-value you choose depends on the kind of heat insulator and soundproofing material you want. For the best soundproofing results, use R49 as it’s an all-around material, notwithstanding its price.