Hybrid vinyl planks come with acoustic underlay attached to them. For example the one that I am after has LnTw of 40 db.

The question is if I install that on top of an extra 2mm acoustic underlay, say, LnTw of 50 db, does that make a better soundproofing in an apartment with concrete floor compared to installing the vinyl plank with its own attached underlay? Or does that make no difference?

  • Is the problem having sound travel down through the concrete floor from apartment to apartment? Or, is the problem from someone walking on the floor and sound radiates out into the room?
    – Lee Sam
    Jan 23 at 5:41
  • @LeeSam does that make a difference? How to solve the both problems?
    – xbmono
    Jan 23 at 11:18
  • 1
    Be sure to check the spec sheet/installation instructions for your flooring. Some specifically say that they should not be installed over any other underlayment. Some may go so far as to void the warranty if they're not installed directly over concrete/plywood/solid wood underlayment.
    – FreeMan
    Jan 24 at 19:16

1 Answer 1


There are two kinds of “sound control” problems: 1) airborne sounds, and 2) impact sounds.

  1. Airborne sounds (talking, tv, etc.) is the easiest to control and it looks like you’ve solved that issue.
  2. Impact sound (closing doors, heels clicking on floor from walking, etc.) is much harder to control. Impact sound travels through building materials (floor joists, concrete, etc.) much faster and much more efficiently. In order to control impact sound, you need to isolate the surrounding material. Some of these problems are “built in” and cannot be resolved easily (or cheaply). We try to 1) stop floor joists and underlayment from extending under a party wall, 2) provide separate party walls between rooms, and 3) stop joists from crossing from room to room. Obviously it’s too late for those techniques, so now you need to consider techniques for each individual problem.
  • 1
    Thanks but that's not my question. I understand that I can't resolve this kind of issue 100 percent but I want to know if the impact sound is reduced when we add additional underlay to a floor that has already got acoustic underlay attached... or it doesn't make difference and a floor with its own attached underlay will have the same impact sound reduction?
    – xbmono
    Jan 24 at 2:32
  • All materials have a STC rating (sound transmission rating). The higher the rating the better reduction in transferring sound through systems. Yes, adding more material will help reduce sound transmission. I’d Google “STC” and you’ll see what types of materials reduce sound the most. The more you add, the higher the STC rating, and the more reduction.
    – Lee Sam
    Jan 24 at 5:03

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