Sound attenuation batt insulation, often called SAB, is a thin, unfaced batt made to fill interior walls and ceilings for noise control. It usually comes 2.5 to 3.5 inches thick, in 16 or 24 inch widths, made of fiberglass or mineral wool. On its own, SAB adds about 3 to 6 STC points to a basic wall. Paired with the right drywall and framing, it helps walls reach STC 45 to 55.
People are often surprised that the batt is only part of the answer. At Grizzly Insulation Co, we install sound batts in Denver homes, offices and multifamily buildings. Here’s what the specs mean, which STC numbers to expect and where SAB is worth the money.
What Is Sound Attenuation Batt Insulation?
Sound attenuation batt insulation is a lightweight, unfaced batt designed to soak up sound inside wall and ceiling cavities. “Attenuation” just means reducing. The batt cuts down sound bouncing inside the hollow wall, so less noise passes to the next room.
SAB looks like regular insulation, but it’s built for a different job. It’s thinner than a thermal batt and has no paper facing. It’s often sized to fit steel studs, which are common in commercial buildings. Our guide on whether insulation helps with sound covers the basics.
What Are the Typical Specifications for Sound Attenuation Batts?
Here are the specs you’ll see on most product sheets. Exact numbers vary by brand, so always check the data sheet for your product.
Spec
Typical range
Material
Fiberglass or mineral wool
Thickness
2.5, 3 or 3.5 inches
Width
16 or 24 inches, to fit stud spacing
Facing
Unfaced
Sound absorption (NRC)
About 0.85 to 1.05
Fire rating
Class A flame spread, ASTM E84
Noncombustible
Mineral wool versions pass ASTM E136
NRC (noise reduction coefficient) measures how much sound a material soaks up. A rating near 1.0 means it absorbs almost all the sound that hits it. Mineral wool versions are also noncombustible.
What Should You Check on a Sound Batt Spec Sheet?
Check the items that affect fit, fire and sound. Here’s a short list to look for:
Standard: ASTM C665, the standard for blanket insulation in framed walls. Unfaced sound batts are Type I.
Thickness and width: Match your stud depth and spacing. Steel studs often need 2.5 to 3 inch batts.
Fire tests: ASTM E84 flame spread and smoke results. Mineral wool should also list ASTM E136 noncombustible.
Sound absorption: An NRC value tested under ASTM C423.
Tested walls: A list of wall designs with STC results and test report numbers.
Those tested walls are the most useful part. They show exactly which drywall, studs and spacing produced the STC number on the sheet.
What Does an STC Rating Mean?
STC stands for sound transmission class. It’s a single number that shows how well a whole wall or floor blocks airborne sound like voices and TV. Higher is quieter. Labs test it under ASTM E90.
Here’s what different STC levels feel like:
STC 30 to 35: Normal speech is easy to hear and understand through the wall.
STC 40 to 45: Loud speech is heard but hard to make out.
STC 50 to 55: Loud speech is faint or not heard. Music is muffled.
STC 60 and up: Most household sounds are blocked.
Here’s the key point. STC belongs to the whole wall, not the batt. A batt has no STC rating on its own.
How Many STC Points Does Sound Attenuation Batt Insulation Add?
Usually about 3 to 6 points in a basic wood stud wall, and more in steel stud walls. Typical lab results look like this:
Wall build
Typical STC
2×4 wood studs, 1/2″ drywall each side, empty
About 33 to 35
Same wall with sound batts
About 37 to 39
Steel studs with sound batts
About 42 to 45
Resilient channel on one side, plus batts
About 45 to 50
Staggered or double studs, plus batts
About 50 to 56
These ranges come from published lab tests of common walls. The insulation industry’s acoustical performance guide shows tested wall designs if you need exact numbers for a project.
Can Sound Batts Alone Soundproof a Room?
No, this is the most common misconception we hear, and it doesn’t hold up. A sound batt in a standard wall only adds a few points. The drywall and studs still carry sound from one side to the other.
So where does the “soundproof batt” idea come from? Mostly from packaging. The big STC numbers on the bag come from a full tested wall, with special framing and extra drywall. The batt alone won’t get you there.
If quiet really matters, we’d tell you to treat the wall as a system. Add sound batts, then add mass and separation:
Use two layers of drywall on one or both sides.
Add a resilient channel or sound clips so drywall doesn’t touch the studs directly.
Seal every gap with acoustic sealant, including outlet boxes.
Use staggered or double studs for walls that need STC 50 or more.
Where Should You Use Sound Attenuation Batts?
Use them where noise between rooms bothers you. These are the spots we recommend most:
Bedrooms next to living rooms or bathrooms.
Home offices and media rooms.
Bathroom walls, to cut plumbing and fan noise.
Laundry rooms next to living space.
Floors between levels, to soften voices and TV.
Office partitions and conference rooms.
New Denver townhomes and infill homes often share walls or stack bedrooms over living rooms. Those are the builds where we hear the most noise complaints, and where sound batts pay off fastest.
For finished walls, sound batts can’t be added without opening the wall. Dense-pack cellulose is an option there. See our guide to insulating existing interior walls.
Does the Building Code Require Sound Attenuation in Walls?
Yes, between units in multifamily buildings. The International Building Code (Section 1206) requires walls and floors between dwelling units to reach STC 50 in lab tests, or STC 45 when tested in the field. Many Denver apartments, condos and townhomes have to meet this.
Single-family homes don’t have a sound requirement. That makes SAB an upgrade choice, not a code item, in a typical house. If your project is a multifamily or office build, our commercial insulation team can match the tested wall design.
Do Sound Batts Help With Fire Ratings Too?
Mineral wool batts often do. Many fire-rated wall designs call for mineral wool in the cavity. That’s why rated walls between units often use mineral wool sound batts. Fire ratings belong to the tested wall, though, not the batt.
Is Mineral Wool or Fiberglass Better for Sound Batts?
Both work well, and the STC difference is small in most walls. Mineral wool is denser, fits snug without staples and won’t burn. Fiberglass costs less and is lighter to handle.
In our experience, mineral wool is worth the small extra cost for bedrooms and offices. It stays put in the cavity and cuts mid-range noise a little better. For more batt options, see our batt insulation guide. If the wall is also an outside wall, compare our R-15 insulation guide, since you’ll want thermal batts there.
Conclusion
Sound attenuation batt insulation is a smart, low-cost start. It soaks up sound inside the wall and adds a few STC points. Pair it with extra drywall, resilient channel and good sealing, and you get the real quiet you’re after.
Planning a quiet bedroom, office or media room in your Denver home? Grizzly Insulation Co can help you build it right. We’re BPI Certified and an Xcel Energy rebate partner.
Call (303) 854-6221 or see our batt insulation services. Ask us about upgrades for Denver condos too.
Sound Attenuation Batt Insulation Specifications Explained With STC Ratings and Where to Use Them
Sound attenuation batt insulation, often called SAB, is a thin, unfaced batt made to fill interior walls and ceilings for noise control. It usually comes 2.5 to 3.5 inches thick, in 16 or 24 inch widths, made of fiberglass or mineral wool. On its own, SAB adds about 3 to 6 STC points to a basic wall. Paired with the right drywall and framing, it helps walls reach STC 45 to 55.
People are often surprised that the batt is only part of the answer. At Grizzly Insulation Co, we install sound batts in Denver homes, offices and multifamily buildings. Here’s what the specs mean, which STC numbers to expect and where SAB is worth the money.
What Is Sound Attenuation Batt Insulation?
Sound attenuation batt insulation is a lightweight, unfaced batt designed to soak up sound inside wall and ceiling cavities. “Attenuation” just means reducing. The batt cuts down sound bouncing inside the hollow wall, so less noise passes to the next room.
SAB looks like regular insulation, but it’s built for a different job. It’s thinner than a thermal batt and has no paper facing. It’s often sized to fit steel studs, which are common in commercial buildings. Our guide on whether insulation helps with sound covers the basics.
What Are the Typical Specifications for Sound Attenuation Batts?
Here are the specs you’ll see on most product sheets. Exact numbers vary by brand, so always check the data sheet for your product.
NRC (noise reduction coefficient) measures how much sound a material soaks up. A rating near 1.0 means it absorbs almost all the sound that hits it. Mineral wool versions are also noncombustible.
What Should You Check on a Sound Batt Spec Sheet?
Check the items that affect fit, fire and sound. Here’s a short list to look for:
Those tested walls are the most useful part. They show exactly which drywall, studs and spacing produced the STC number on the sheet.
What Does an STC Rating Mean?
STC stands for sound transmission class. It’s a single number that shows how well a whole wall or floor blocks airborne sound like voices and TV. Higher is quieter. Labs test it under ASTM E90.
Here’s what different STC levels feel like:
Here’s the key point. STC belongs to the whole wall, not the batt. A batt has no STC rating on its own.
How Many STC Points Does Sound Attenuation Batt Insulation Add?
Usually about 3 to 6 points in a basic wood stud wall, and more in steel stud walls. Typical lab results look like this:
These ranges come from published lab tests of common walls. The insulation industry’s acoustical performance guide shows tested wall designs if you need exact numbers for a project.
Can Sound Batts Alone Soundproof a Room?
No, this is the most common misconception we hear, and it doesn’t hold up. A sound batt in a standard wall only adds a few points. The drywall and studs still carry sound from one side to the other.
So where does the “soundproof batt” idea come from? Mostly from packaging. The big STC numbers on the bag come from a full tested wall, with special framing and extra drywall. The batt alone won’t get you there.
If quiet really matters, we’d tell you to treat the wall as a system. Add sound batts, then add mass and separation:
Where Should You Use Sound Attenuation Batts?
Use them where noise between rooms bothers you. These are the spots we recommend most:
New Denver townhomes and infill homes often share walls or stack bedrooms over living rooms. Those are the builds where we hear the most noise complaints, and where sound batts pay off fastest.
For finished walls, sound batts can’t be added without opening the wall. Dense-pack cellulose is an option there. See our guide to insulating existing interior walls.
Does the Building Code Require Sound Attenuation in Walls?
Yes, between units in multifamily buildings. The International Building Code (Section 1206) requires walls and floors between dwelling units to reach STC 50 in lab tests, or STC 45 when tested in the field. Many Denver apartments, condos and townhomes have to meet this.
Single-family homes don’t have a sound requirement. That makes SAB an upgrade choice, not a code item, in a typical house. If your project is a multifamily or office build, our commercial insulation team can match the tested wall design.
Do Sound Batts Help With Fire Ratings Too?
Mineral wool batts often do. Many fire-rated wall designs call for mineral wool in the cavity. That’s why rated walls between units often use mineral wool sound batts. Fire ratings belong to the tested wall, though, not the batt.
Is Mineral Wool or Fiberglass Better for Sound Batts?
Both work well, and the STC difference is small in most walls. Mineral wool is denser, fits snug without staples and won’t burn. Fiberglass costs less and is lighter to handle.
In our experience, mineral wool is worth the small extra cost for bedrooms and offices. It stays put in the cavity and cuts mid-range noise a little better. For more batt options, see our batt insulation guide. If the wall is also an outside wall, compare our R-15 insulation guide, since you’ll want thermal batts there.
Conclusion
Sound attenuation batt insulation is a smart, low-cost start. It soaks up sound inside the wall and adds a few STC points. Pair it with extra drywall, resilient channel and good sealing, and you get the real quiet you’re after.
Planning a quiet bedroom, office or media room in your Denver home? Grizzly Insulation Co can help you build it right. We’re BPI Certified and an Xcel Energy rebate partner.
Call (303) 854-6221 or see our batt insulation services. Ask us about upgrades for Denver condos too.
Frequently Asked Questions
Sound batts are thinner, unfaced and sized for interior walls. Regular batts are made for heat control in outside walls.
Batts don’t have an STC rating on their own. They usually add about 3 to 6 STC points to a basic wall.
Yes. Unfaced thermal batts also absorb sound. Sound batts just fit interior walls better.
Most are 2.5 to 3.5 inches thick. Pick the thickness that fills most of your stud cavity.
Yes. They soften voices and TV between floors. Impact noise like footsteps needs more than insulation.
Yes. Dense-pack cellulose or blown fiberglass insulation works in closed walls.
Yes, especially on shared walls and between floors. Add extra drywall and sealing for the biggest gain.