Noise reduction — basement ceiling
itserich
| Posted in General Questions on
I have installed rigid foam between the joists in a basement ceiling.
I would like to reduce noise because I have dogs and plan to use the basement as a primary living space. The goal would be to reduce outside noise so the dogs do not react to noise.
I bought some Mass Loaded Vinyl and Roxul Safe N Sound.
The thought is to put a layer of MLV under the foam and Roxul under the MLV, providing a fire barrier and noise reduction.
That would leave the joists uncovered.
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Replies
Erich, If I undersand your post correctly, you want to attenuate sound coming from above while leaving the bottoms of the floor joists exposed in the basement. While what you propose goes some way towards this goal I think you will be disappointed with the results unless you do something to de-couple the structure and provide a continuous layer of material below the joists. I would suggest using resilient channels to hang two layers of 5/8" drywall caulked at the perimeter before taping.
When trying to attenuate sound, the most reliable way to predict how well the results will perform is to use a complete tested assembly. You can find a number of different options by seaching something like "STC 60 ceilings" on Google.
Good luck!
Thank you Malcolm. The resilient channel is interesting, similar to thermal bridging. In this case, I am the only human, the noise to be reduced is coming from outside the house, other dogs and kids. I don't know for certain but it seems a resilient channel would help with vibration type noise from floor to ceiling, but I have a lot to learn.
Here is a brief video by Roxul discussing Airborne Noise and Impact Noise.
http://diywithroxul.com/en-us/diy-videos/soundproof-ceiling-between-floors.html
Erich, sound is kind of like moisture—you can seal 98% of the wall, but a small penetration will defeat the rest. Note in the video link in your No. 3 response above, the first job was to seal all holes with acoustical sealant. This is why windows and doors are typically a weak spot. Triple glazed airtight windows would help a great deal. At the very least, make sure your thresholds and weatherstripping perform flawlessly.
The most difficult hurdle will be attenuating the deep bass sounds, such as trucks going by or teenagers with boom boxes in their trunks. For this, only mass separated by air channels will work. I built an isolation booth for a professional sound studio once, and we used many layers of drywall on both sides of parallel walls that were independent of each other. All layers of the drywall had to be taped, just like layers of foam should be taped independently on a wall or roof. The plates were also isolated from the floor and ceiling.
Thanks David. I have cut and cobbled 2 inches of expanded polystyrene between the basement ceiling joists. Did not use an acoustical caulk but will for the rest of it. The street is a dead end / cul de sac so the main source of noise is kids playing and dogs barking. I am planning to work on only half the basement and there are two small windows and I will seal the north window.
At this point I will probably cut and cobble Mass Loaded Vinyl below the polystyrene and then add the Safe N Sound. Safe N Sound is good fire and sound protection. Then I can add a resilient channel if necessary. A main consideration is ceiling height.
The walls do not have a space constraint. I am waiting to make sure there is no water problem before finishing them.
Thanks for the comments!