do they sell sound proofing insulation?

Question

I am looking to finish my basement and I want to insulate the ceiling and walls. Is there a good brand of insulation out there that prevents sound from traveling through the walls. Obviously insulation will not prevent all sounds, but if there is a brand that stops the majority of sound, that would be great

Answer 1

Note the difference between sound absorption, which makes the room you're in quieter, and sound resistance, which makes the room above or beside you quieter. Insulation is great at absorbing sound but not so good at resisting sound. The answers here that talk about mass and resilience are right on target for resistance. Sand filled block walls. Double layer drywall mounted on resilient channels is good for walls and ceilings. Then add insulation inside the drywall chamber to slow down any sound that gets through. But here is the key that no one has mentioned: seal all penetrations, even the smallest holes, so your ceilings and walls are air tight. Plumbing and electrical penetrations, and ductwork of course, are all notorious offenders. For this air sealing, spray insulation is good.

Answer 2

When you go somewhere to purchase insulation, it will have a rating on the product which will tell you about the sound-deadening performance of each product.



I am a contractor and have done many finished basements which we did soundproofing on. Insulating the walls will help with heating bills but won't effect the sound. The main place to be concerned about is the ceiling. A good fiberglass batt insulation (rated for sound control) does a fair job but the killer problem areas are the wires for drop-ceilings and the ductwork. Metal transfers the vibrations (sound) through the floor. Metal heat duct is just like putting a trumpet into the floor above, a simple conversation can be heard loud and clear emanating from the floor vent. I have used spray-foam insulation (polyurethane, by the pros, not the canned stuff) to isolate ductwork. For a drop ceiling use plastic hanging material, not the steel wire. If nothing use-specific is available, try large zip-ties (used in HVAC and electrical work) or I have a friend who swears by heavy weedeater cord (but I've never tried it).



Best of luck.

Answer 3

A tenant cannot break a lease due to poor sound insulation unless it is truly extreme. If they can hear someone drop something, it's bad. If they can hear the tv or music, that is normal. There are inexpensive ways to sound proof though. Simple insulation provides a pretty repsectable barrier for soundwaves. I would find out what they are hearing. There may be a huge problem with soundproofing. Or the problem could be the tenant on the other side is just inconsiderate, playing music loudly or watching TV loudly at all hours of the night, etc.

Answer 4

Like most people, you don't understand how sound works. The majority ( about 85%) of sound will travel through the drywall and wood. Empty voids actually reduce most sound. The more dense the material the faster sound can travel through it. However, the heavier the material, the more energy it takes to travel.



Sound proofing is more about 1) designing longer routes for sound to travel or 2) weighing down the path of so that it takes more energy for sound to travel a distance.



For the ceiling the best solution is resilient channels or 1x3 wood straps up before drywall. They need to run perpendicular to the ceiling joists and under no circumstances can you allow a screw from the drywall to touch a ceiling joist. Getting a minimum of two inches away when possible is best. In this setup gravity is going to pull down the drywall and wood strap will become taunt. In order for sound to go through the ceiling it has to push the ceiling up but cannot pull down, which heavily resists half of the sound wave.



On the wall you can't use gravity, but you can design the wall to limit any solid path from side to side. This is the purpose of staggered stud walls and double walls. In a basement I don't know how useful either would be, but they might be worth a study in some situations.



The other two key issues is absorption, and mass.

Mass is easy, the heavier the wall is, the less sound can travel through it. Every time you double mass of the wall, you double the sound resistance overall. 2 sheets of drywall is double of 1. 4 sheets is double of two. 8 sheets is double of 4. You get the idea.



Absorption: this is the conversion of sound to other energy. If you put tar paper between sheets of drywall, the resulting friction that happens when sound travels through converts some sound to heat. More effective is sound reducing treatments. For about a dollar a square foot you can put a glue/gel between the sheets of drywall. The gel has high resistance to movement and will warm up about a 1/10 of a degree when you crank up the volume on a high power stereo.



Insulation provides modest amounts of resistance to the mid range of most people's voices. A wet cellulose install will give you the most bang for the buck on soundproofing. Mainly that is because it seals the cavity and has some amount of mass. Don't expect it to do away with low range sounds. The booms from a stereo will go through the wood studs and joists easily, unless otherwise prepared. Don't expect foam sheets to accomplish anything.



And make certain you seal any edges with caulking before covering with plaster or drywall mud. Due to the nature of drywall mud to have tiny cracks, it is almost worthless as soundproofing or sealant in a sound proofing application.

Answer 5

Cork and styrofoam are both good sound insulators.