Flooring Sound Ratings Guide

IIC: Impact Sound (Footsteps and Dropped Objects)

IIC (Impact Isolation Class) measures how well a floor reduces impact noise heard in the room below. Higher is better. Every 10 points roughly halves the perceived noise. If you live in a condo, apartment, or building with a sound requirement, IIC is the number to focus on.

STC: Airborne Sound (Voices, TV, Music)

STC measures how well a floor blocks airborne sound. The same 10-point rule applies. For most homeowners it's secondary to IIC and matters most when your building specifies both ratings.

ΔIIC: What the Floor Itself Contributes

ΔIIC isolates the flooring product's own sound reduction, independent of the subfloor and ceiling, making it the best number for comparing products on equal footing. A ΔIIC of 23 means the floor adds 23 points of impact isolation over a bare subfloor.

Why Ratings Vary by Test Condition

A suspended ceiling below the floor absorbs sound and raises the score. When comparing against a building requirement, use the "no suspended ceiling" rating, the conservative number HOA policies are typically written against. Every Flooret rating below is the conservative version.

Underlayment and Sound

When flooring includes pre-attached padding, the published ratings already account for it. Adding a second layer introduces flex that can weaken the click-lock joint and is not covered under warranty. If your building requires more, keep the extra layer to 1.5 mm or less and contact us first at support@flooret.com. When there's no attached pad, quality underlayment is one of the most effective ways to improve IIC.

Flooret Sound Ratings

Modin LVP comes with pre-attached IXPE underlayment, so no separate pad is needed to hit these numbers. Tested over a 150mm concrete slab with no suspended ceiling:

• Signature, Microbevel, Craftsman, Herringbone: IIC 59, STC 53, ΔIIC 23
• Base: IIC 54, STC 53, ΔIIC 23

Signature and Craftsman deliver near-premium impact isolation with no extra underlayment cost.

Silvan Resilient Hardwood achieves IIC 55 and STC 55 tested over an 8" concrete slab, offering genuine hardwood beauty with sound performance that clears the code minimum on its own. If you are installing Silvan in a floating installation, you can apply our Acoustic Underlayment, which features an IIC 73 and STC 72.

Arista Laminate is tested under European acoustic standards, so a direct IIC comparison isn't published. Its built-in underlayment achieves a Silence Index of ≥65dB under ASTM E492-09 and an impact noise reduction of ΔLw 17dB under ISO 717-2, strong marks for a laminate floor. If your building has a specific IIC requirement, contact us before purchasing and we'll help you confirm compliance.

Spec sheets for all collections are in our Technical Documents.

Common Questions

Does my subfloor affect the rating I'll actually get?
Yes. Published ratings reflect a specific test assembly, usually concrete. Wood subfloors and suspended ceilings generally improve real-world performance, so treat the published numbers as a conservative baseline.

Can I add underlayment under Modin or Arista to improve sound?
Both come with attached underlayment, and stacking a second soft layer can weaken the click-lock joint over time. If your HOA requires it, keep the additional layer to 1.5 mm or less and email support@flooret.com before installing.

Do I need to worry about a specific rating?
In a single-family home, probably not. In a condo or apartment, check with your HOA or building management before you buy. We're happy to help you match a collection to your requirement.

Questions? Email support@flooret.com or call 1-800-700-8122. M-F, 8 AM–7 PM CST.