What is sonic impact of filling in floor above HT room?

[Colin]

I am planning, maybe someday soon, to pull up the ugly pile carpeting in the 14-ft2 master bedroom above my 18-ft2 HT living room. Once the carpet is up, the floorboards are exposed. I have not looked, but it should be simple to pull the boards up and stuff insulation between the joists:

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q What is standard joist height and spacing for 1980 TH in FL?

q If I pour in loose Styrofoam or lay in fiberglass, what difference will this make to the bright sound in the HT room below?[:^)]

[michael hurd]

1. No idea. Floor joists should be 18" on center.

2. Absolutely no difference to the bright sound in the room. It will however attenuate ( reduce ) sound transmission from floor to floor.

You are barking up the wrong tree here.

[dragonfyr]

http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/90246.htm

http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/90247.htm

http://soundproofing.org/infopages/channel.htm

Unfortunately most of the sound is transmitted via conduction between the rigidly coupled elements. Fill between the components will have little effect.

The reflective component of the surface below will additionally not be effected to any great extent.

[IndyKlipschFan]

Colin if you take the floor up?? WOW, kinda nuts, but if you must THAT alone will be a big job. even if you could??

I think perhaps a covering over the floor of some kind.. then a very good pad then dense carpet would do more in your case.

In my HT below in the lower level... I have a false ceiling that does NOT touch the beams above. Lots of insulation.. We wrapped pipes.etc etc double drywall, we will just have to see. Some of these tricks make for wonderful readings.. Some of it, I am sure, is almost snake oil..

That said.. I would be very to rip up the floor you already have..mine has like 10k screws to screw it all down into the beams.. I am sure nearly impossible to do from above!

[picky]

Colin: I wish to recommend you consider laying down acoustic blocking membrane beneath the floor covering you choose, whether it be carpet or wood flooring. It can help reduce the overall noise level by at least 25 db in most applications.

Try Sonex ProSPEC Barrier: http://www.quietnoise.com/barriers.htm

[formica]

q What is standard joist height and spacing for 1980 TH in FL?

q If I pour in loose Styrofoam or lay in fiberglass, what difference will this make to the bright sound in the HT room below?[:^)]

1980 Town House? Ok, under your carpet you will find 4' x 8' sheets of plywood which extend under the divisions (it's installed before they built the walls). Not a simple task to demolish and replace.

Joist (or perhaps truss) spacing and height will vary according to the span... 2x10" @ 16 c/c used to be common in the 70's for 10 to 12' spans, but the 80's saw the introduction of engineered floor trusses and joists with longer spans and varied spacing.

As already mentionned, neither will help with the sound within your room below.

OTOH, to reduce sound transmission, the idea is to convert some of that sound into heat. That requires an open cell insulation like fibreglass wool, cellulose, etc... Styrofoam is generally closed cell (ie: it doesn't soak up water) and relatively ineffective.

If you really want to this, I can think of several methods that would require less work from below.

Rob

[colterphoto1]

I agree with Formica. Probably 2x10's spaced 16 on center (14.5" between). If it's plywood or any other 4x8' material- don't attempt to pull it up. It should be glued as well as nailed. And it not only is the floor, it is a structural membrane that keeps the joists from racking sideways.

Insulating won't make a huge difference in the sound transmission, or brighness of either room. However, you could choose to drill holes and install blown-in cellulose. It might dampen foot falls from the room above into your HT, but doubtful would contribute much towards loud HT sound to the bedroom.

Michael

[picky]

Another thing you might consider is to mount a false celing in your HT that is suspended only a couple of inches from your original ceiling. It would be made with drywall that is suspended using resilient channel (RC). This will provide you with a floating ceiling that would eliminate the need to tear up the floor upstairs and perhaps results in the biggest reduction of sound transmission possible between the two floors. All of the seams and joints would be sealed using resilient, elastomeric latex caulk.

[dragonfyr]

Pardon me for repeating this, but I think you will find all the options for both floor and ceiling** covered in the various links complete with their effectiveness rating...

http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/90246.htm

http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/90247.htm

http://soundproofing.org/infopages/channel.htm

Also, adding insulation between the tightly coupled surfaces will not reduce noise transmission through the wall/floor/ceiling as the sound is conducted via the tightly coupled surfaces! What is placed between them is nice, but of little insulative value due to the primary conductive path! And the insulation will have negligible effect on the reflective coefficients of the surfaces. And it is the reflective characterisitis which will overwhelmingly predominately determine the 'brightness' of the room as a result of sound eminating from within the same room.

But to address your PRIMARY question which we all have pretty much ignored in addressing the conduction of sound through the surface:

If you need more info on the reflective coefficients of various surfaces (and remember, they reflect different frequencies differently!!! - they are not linear systems!!), PM me as I have spreadsheets full of measured values for various materials.

Good luck!

** They are also applicable to walls

[artto]

There is no standard joist size or spacing, depends on the local building codes and type of construction, load to be carried, etc. In my house for instance, there are 2x12 16o.c. on one side of the house and 2x12 12o.c. on the other side because the upper level is cantilevered on that side.

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As dragon said, filling the cavity will have little or no effect on the room acoustics unless you go with a very dense rigid insulation in which case you may get some bass trapping effect. It may help dampen some resonances and mid/treble sound transmission. If you were installing this as part of new construction it might be worth the expense and time.

I prefer Pickys suggestion, using something like Sonex ProSPEC Barrier or Auralex Sound Blok, both of which are very dense 1/8 compressed limp mass vinyl which is actually denser than lead and does a respectable job of reducing both air bourn and impact type sound transmission. To be most effective at reducing impact related noise it must be installed close to the noise source (ie: on the floor, not the ceiling). Lay this down over your existing floor board. Use a high density carpet padding and carpet. Depending on what kind of floor board (ie: plywood) you have, it might be good to screw it down.