Your approach to sound attenuation???
Hello all,
I am finishing a basement in a six year old house. The finished basement area will have a TV area/family room, bar, bath, guestroom and sitting area.
Homeowners have expressed a desire to reduce noise from upstairs PVC plumbing (i.e. upstairs toilet flushes and everyone in the basement can hear it) as well as reduce the noise of foot traffic heard from the main floor.
I have gotten conflicting advice from various subcontractors on the best approach to help reduce this problem. The drywallers say 2 layers won’t help, one insulation guy says “cellulose is a waste of money, use batts.”
I don’t expect to completely eliminate all noise, because that isn’t in the budget, but I would like to hear some advice on cost effective solutions that have worked for you.
So far I have considered any one of the following:
Two layers of sheetrock on the ceiling
Insulating the truss cavities with blown in cellulose
Hat channels mounted to the trusses w/ SR attached (no insl)
Mass loaded vinyl attached to the underside of the trusses, prior to SR
F/G batts in the truss cavities (cheap but IMO ineffective)
Your advice is appreciated.
Replies
The hat and double SR will help a lot
Spray foam on the pipes or around it will absorb some sound too. Cells almost as good
I don't get the insulation guy's statement. For most purposes he is dead wrong, but maybe there is something about the context - or maybe it is just that he only does FG batts
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F/G batts in the truss cavities (cheap but IMO ineffective)
Why do you say they are ineffective?
We install R-19 in most of finished basements to mitigate noice transfer. There certainly are better alternatives but for the money spent batts do a pretty good job IMO.
CAGIV,
In this case, we have a 16" tall web floor truss. It just seems like putting 6" batts at the bottom chord wouldn't really help that much. You still have 3 1/2" of chord material to transfer sound vibration to the drywall and you have 10" of unfilled air space above the batts.
I have also used R-19 batts in other TJI floors and when all is said and done, I just don't think know how much difference it makes.
Homeowners have expressed a desire to reduce noise from upstairs PVC plumbing (i.e. upstairs toilet flushes and everyone in the basement can hear it)
Isn't that what the cast iron folks brag on?
PAHS Designer/Builder- Bury it!
We'll typically use unfaced fiberglass batts in all walls and 5/8" sheetrock everywhere. Sound channel on the ceiling. It's relatively cheap and creates a reasonable amount of sound deadening for cheap.
On drain pipes I like the idea of encasing them in spray foam. Ice and water shield can be wrapped around the pipes and the rubbery nature of the project keeps a lot of sound out. There are also sound deadening wrappes made for cars and airplanes that would work well.
Beer was created so carpenters wouldn't rule the world.
The article in the March 06 JLC Innovations in Sound Control pretty much covered the topic. I was at a seminar at JLC Live last week that pretty much followed the article's content. They also suggested SoundSense, a company that offers consulting/engineering services and distributes of related products which had a booth just across from the stage.
If you are going to do it yourself I have a few suggestions. First be absolutely ruthless about air sealing all wall/ceiling penetrations including electrical boxes with foam or caulk. I believe that mineral wool is supposed to be a superior sound insulation compared to glass bats. If you plan on two layers of rock use 1/2" and 5/8". Finally buy some of their LVA pipe wrap to wrap the drain line with.
Geez, I'm starting to sound like a plug for Roxul- but as you've said, it really is true. Mineral wool batts, especially the high density ones (ie. Roxul "Safe n Sound") are much better at sound attenuation than fibreglass is. We built a few compressor enclosures and the sound attenuation you can get with just batts in a box is surprising.
I understand that resilient channel helps quite a bit by de-coupling the sheetrock from the wood above.
Renoun,
Thanks for the link to the website. I had read that article and had considered some of the suggestions. The budget doesn't allow for a consultant, but we are going to try to use the advice given here.
Anything you use as a barrier will help, as long as it has some decent mass. The drywall will help, batts in addition will help, the rubber membrane or sprayed-on foam on the pipe will help. Start with what can go directly on the pipe, try it and see how much more attenuation is needed. Chances are, foam on the pipe with drywall will make a huge difference. Add the batts and you probably won't hear it much. Also, if you can isolate the pipe from any direct contact to the framing, you'll keep the sound from being transferred to an area right over people are sitting, becoming a distraction.
"I cut this piece four times and it's still too short."
Just did mine.
Use mineral wool, wrap all pipes, cut off all open slot (outlets lights etc) with foam insulation, do not use hat channel but rather resiliant channeling to suspend rock from joists, two thicknesses of different types of material (1/2" rock and 1/2" homosote maybe), or as the advice above use 1/2" and then another layer of 5/8" rock, leave a 1/2" gap separating cieling from the walls and fill with soft foam and hide with small mouldings. Weatherstrip solid entrance door to room with seal gasket and bottom seal, carpet on floor above helps, have absourbant materials in room like carpeting pillows etc.
Good luck.
I've heard of wrapping PVC or ABS pipe with lead sheets to cut the noise. As for foot traffic, what's worked exceptionally well for us is the box inside a box approach. Frame up a whole new set of walls and ceiling joists, not touching the existing structure except where the sole plates rest on the slab. This worked on a practice room for a professional drummer, and on the TV Foley stage at Paramount.
-- J.S.
Hat channel, fill cavity with batts, one layer drywall, and for good measure lock the door to the upstairs bathroom.