If you live over someone, hard-surface flooring is not a solo decision. HOAs and co-ops often want documentation: underlay type, thickness, lab ratings. Your job is to pick a product that meets the paper and still works with your flooring brand’s lock system.
Start with the rules, not the rug sample
Get the renovation package in writing. Look for required IIC/STC, maximum finished height, approved product lists, and whether floating wood/LVP is even allowed. Some buildings still want carpet in bedrooms. Arguing online will not rewrite the bylaws.
IIC in plain English
IIC is about impact noise—heels, toys, dropped spoons—how much energy makes it through the assembly. STC is more about airborne sound. Lab numbers come from a specific floor/ceiling recipe. Your building is not that lab. Still, higher IIC underlays with published PDFs are what boards understand. Screenshots of five-star reviews are not.
Chasing silence with three inches of soft foam under rigid LVP is how you trade one complaint (noise) for another (failed locks). Density and the right product class beat bulk.
What to buy when the board wants “quiet hard floors”
- Underlay with published IIC/STC for a comparable assembly
- Explicit approval for your floor type (laminate, engineered float, LVP)
- Thickness that still clears doors and meets building height limits
- A moisture story if you’re over a slab podium or gypcrete oddity—ask the building engineer when confused
Keep the packaging label and tech sheet in a folder with the HOA approval email. Future you will thank present you when someone claims you used “non-approved foam.”
Install discipline that protects the rating
Gaps, missing underlay under closets, and hard point loads can undo expensive pad. Cover the whole floating field as specified. Use soft glides on furniture. Area rugs help the room; they are not a substitute for underlay the board required.
Gypcrete and light structures
Some condo slabs are not the thick concrete of your imagination. Ask what you’re actually floating over. Sound and fastener rules change. “Works in my mom’s ranch house” is not multi-family engineering.
Acoustic-leaning starting points
Straight answers
Is a higher IIC always better?
Usually better for board compliance, but only if the underlay is still compatible with your flooring. A perfect lab number on an illegal pad is still a failed inspection.
Will rugs replace underlay for HOA rules?
Almost never. Rugs help lived-in sound. Documentation usually wants underlay under the hard surface field.
Can I glue down hardwood in a condo for less noise?
Maybe, if the building allows it and the substrate cooperates. That’s a different system than floating underlay—get written approval before you buy materials.
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