Author Topic: Soundproofing a floor with old floorboards and services underneath  (Read 3299 times)

fool_on_the_hill

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Hi all. Newbie here, hoping to benefit from a more experienced opinion or two. I'll be sure to post an update after I've done the work (hopefully not in the "Soundproofing Jobs Gone Bad!" forum!).

I'm working out the best way to soundproof a floor to a neighbour below. Key facts are:
  • This is a fairly small room (about 6½' x 8') that will be used as a music practice room (singing, acoustic guitar, possibly occasionally electric guitar through a *very* small (1 watt) amp)
  • The neighbour below isn't especially noise sensitive at all, at least within reasonable hours of the day (and I don't plan on using the room for anything noisy late at night). I'm doing this as much for my own privacy as for my neighbour's peace and quiet.
  • Given the above, I'm not worried about impact noise, only airborne (although I expect to get some impact noise benefit). I'm mainly aiming to cut out highs and mids that will be somewhat louder than typical TV/conversation levels
  • There's currently *nothing* between my floorboards and the drywall ceiling of the neighbour below (apart from eight inches of air and some miscellanous construction debris that's probably been there since the '70s)

I was planning to put acoustic mineral wool under the floorboards, seal up the gaps with acoustic mastic/sealant, then put down soundproof mats followed by productised soundproof underlay available from a nearby company (basically a sandwich of two layers of very heavy soundproof matting bonded either side of a thick underlay).

Problems and questions are:
  • There are a *lot* of gaps between floorboards (some of them quite big) particularly where the old boiler used to be (it was removed several years ago to be replaced with a moden combination boiler on the wall). See the attached photos. How important is it to seal all of these up, and any suggestions on how to do so?
  • There are loads of services running under this floor (a very large number of water pipes, plus slightly complicated lighting system for the neighbour's bathroom below), which make it pretty much impossible to lay AMW under most of it. Is it worth trying to lay it where I can, or would the above-floor soundproofing be sufficient for what I want to achieve?

Thanks in advance for any help.

Randy S

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Re: Soundproofing a floor with old floorboards and services underneath
« Reply #1 on: May 21, 2012, 09:53:10 PM »
How high can you raise the floor?
Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

fool_on_the_hill

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Re: Soundproofing a floor with old floorboards and services underneath
« Reply #2 on: May 23, 2012, 09:15:03 PM »
I don't mind losing a bit of height, but more than an inch or so might start to look odd. I was thinking of putting down a layer of plywood or cement-impregnated chipboard first and sealing that up instead of the floorboards. It would add on another quarter inch.

Randy S

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Re: Soundproofing a floor with old floorboards and services underneath
« Reply #3 on: May 23, 2012, 10:11:58 PM »
Ok, 1" might be enough to get a decent airborne sound reduction but might not be enough to reduce the impact footfall issue.

Absolutely fill all cavities with insulation and if sealing the gaps between floor boards is too much to accomplish than go ahead and use 1/2" cement board then seal all seams.

After this is finished we can assess how much more reduction you need.

You want to do this methodically so we add enough mass to get the reduction your looking for.

Randy Sieg

Super Soundproofing Co
www.soundproofing.org
888-942-7723
Ph. 760-752-3030
Fax.760-752-3040

 

anything