Sound-deadening underlayment for hardwood floor installation
Daniel F. Vellone| Posted inGeneral Questionson
I’ll soon be installing hardwood on my second floor and wonder if it’s worth considering a sound-deadening underlayment, and which ones might be recommended.
The subfloor is 5/4 hemlock planking installed over 5×8 joists, which comprise the first floor finished ceiling.
Thanks, Daniel
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Replies
When you say sound deadening what is your goal?
The way I see it, if you keep the plank subfloor squeaks are inevitable after a few years because each plank will absorb moisture from the air in the summer and dry in the winter. The plank will cup in the summer and flatten in the winter this will loosen any fastener so the floor will move and squeak in time.
If your goal is to limit the sound of voices between the spaces you should fill the joist bays with Rockwool.
If your goal is to limit the sound of foot traffic an isolation layer and a mass layer.
Walta
The goal is to install one of the underlayment options available that would best perfrom given my limitations. This is a timberframed structure and my preference is to maintain the open framing.
Quiet Walk Plus from Green Building Supply might be a good option for you. It insulates a bit, provides a vapor barrier, and has a bit of "give" which may help with the sound transfer.
Most of the typical underlayment that are around 1/8" thick only work for absorbing impact noise over a concrete slab, they do almost nothing in a wood framed structure. You can install one, but I wouldn't spend too much money it.
If you want to reduce sound, the typical is to frame sleepers of the plank subfloor, install insulation between the sleepers, new subfloor and floor on top of that. You can reduce the thickness a bit and get better impact performance if you skip the sleepers and go with rigid mineral wool and a floating subfloor on top.
The one underlayment that I've used that does help a bit is this one:
https://www.resisto.ca/en/product/acoustiboard-1968/
It is very heavy and pretty thick, pretty easy install if you have engineered click flooring. Key is to seal around the perimeter and get it as air tight as possible to cut down on transmitted sound as well.