When a tenant calls to complain that they can hear every step from the unit above — or worse, every word from the one next door — it’s already too late. Poor soundproofing is one of those issues that’s nearly impossible to “fix” after move-in without expensive, disruptive retrofits. That’s why smart developers are building STC soundproofing and IIC compliance into their plans from the start.
But here’s the catch: insulation alone doesn’t cut it. Neither does simply doubling up on drywall or hoping carpet will save you from a failed inspection. To reliably meet acoustic standards and keep budgets in check, you need the right sound-dampening materials inside the wall and floor assemblies.
And that’s where Quieture fiber board makes all the difference.
What Are STC and IIC, and Why Do They Matter?
These two acronyms come up again and again in construction projects, ranging from single-family homes to multifamily projects, but what do they really measure?
- STC (Sound Transmission Class): This rating measures how well a wall or floor reduces airborne noise, like talking, TVs, or music.
- IIC (Impact Insulation Class): This one focuses on how well a floor system absorbs impact noise — think footsteps, dropped items, or furniture being dragged.
Building codes in many jurisdictions require a minimum STC rating for multifamily of at least 50. But beyond compliance, meeting or exceeding these ratings leads to quieter, more comfortable living environments and fewer tenant complaints down the line.
Where Standard Builds Fall Short
In a typical 2×4 wall with R13 insulation and a single layer of gypsum board on either side, your STC rating is likely hovering around 34 — maybe 35 if you’re lucky. For floors, a simple slab with vinyl plank might offer an IIC in the low 40s, especially without a proper underlayment.
That’s the issue: the most common residential assemblies just don’t meet acoustic code requirements on their own.
And adding more drywall or switching to floating floors? That can increase costs, add weight, and complicate construction schedules.
So instead of overbuilding, it’s smarter to use a material specifically engineered to address sound at the source — inside the wall and under the floor — where the problem actually begins.
The Role of Quieture in STC Soundproofing
Quieture fiber board isn’t a decorative solution like acoustic treatments. It’s a building material, designed to be built into the wall system as part of the assembly.
Here’s how it helps boost STC ratings for walls:
- Installation placement: Quieture boards fit over the stud framingbehind gypsum board, absorbing airborne noise and reducing sound transfer.
- Stops vibration: The board’s density breaks up structural sound paths and vibration that insulation alone cannot.
- Pairs well with typical wall systems: When used alongside traditional framing methods and gypsum assemblies, Quieture helps wall assemblies reach STC 50 and higher.
And unlike heavier gypsum or mineral-based options, it’s lightweight, easy to cut, and quick to install — saving time without sacrificing results.
IIC Soundproofing: Quieture Under Your Feet
Footfall noise is one of the top complaints in multifamily construction. While carpet helps to solve most of it, today’s preference for hard-surface flooring demands more from your assembly.
Quieture fiber board is designed to be part of a soundproof sandwiching method. This not only boosts IIC performance, but also improves overall sound transmission class flooring characteristics—reducing both impact and airborne noise through floor systems. It can be installed:
- Under floating LVP or engineered wood
- Between the concrete slab and flooring finish
- With adhesives or floating systems, depending on application
This placement helps isolate impact vibrations before they travel through the structure, pushing assemblies into the 58–60+ range on the IIC rating chart flooring scale.
Best of all, it doesn’t require major changes to your floor system or the use of suspended ceilings below.
Insulation vs. Fiber board: Know the Difference
It’s worth repeating: fiberglass insulation does not equal full STC soundproofing. While it helps with airborne sound, it’s not designed to stop the structural vibration that causes the bulk of noise transfer between units.
Quieture fiber board, on the other hand:
- Is denser and specifically engineered for sound dampening
- Blocks both airborne and structural sound
- Functions as a sound barrier, not just a filler
If you’re comparing materials, think of insulation as a necessary layer for energy and basic sound control but Quieture as the key component that actually gets you to compliance.
Don’t Get Tricked by the Term “Acoustic Panels”
People often look for “acoustic panels” when they really mean “soundproofing boards.” But in construction, those two things are not the same.
- Acoustic panels are typically decorative, surface-mounted products meant for echo control in open rooms.
- Quieture boards are structural — installed during construction and designed to go behind drywall or under finished floors.
They’re not interchangeable. If you’re designing a wall or floor assembly to meet STC rating for residential or IIC targets, you need a material that gets built into the system, not one that gets glued on afterward.
Real Project, Real Results
One recent 50-unit mid-rise project started with standard framing and floor specs: STC 45 walls and IIC 52 floors. That wasn’t enough to meet the city’s acoustic code, and the team didn’t want to redesign the structure.
By integrating Quieture into the wall cavity and flooring underlayment:
- Wall assemblies hit STC 52
- Floor assemblies reached IIC 58
- The project passed inspection without overhauls or added delays
Quieture helped the team meet code, control costs, and avoid rework just by making one smart materials decision during framing.
Build Smarter, Not Louder
If you’re developing or building residential structures where acoustics matter — and they always do — Quieture offers a smarter way to meet STC soundproofing and IIC rating requirements. It fits seamlessly into common assemblies, installs easily, and helps you deliver a finished product that’s code-compliant, quieter, and more comfortable to live in.
Need spec sheets, test results, or help designing an acoustic-friendly wall or floor? MPG Building Materials has what you need. Reach out today, and we’ll help you take the guesswork out of meeting your soundproofing goals.
