Sound barrier

[King]

I was looking at a new townhome and was wondering what was better to have the cement blocks between the houses or the new drywall with foam that they are now using between the homes??

[Joseph Meehan]

Check out:

In general you want to block air exchange. Air caries sound very well. (Try opening your car's window as a train is going by.)

Next you want weight. Heavy things (drywall lead sheets etc.) block sound well.

You also want to prevent any direct solid connections. Stagger wall studs or use special isolation devices to keep the sound from traveling through the wall (remember the two cans on a string (well wire actuarially worked) you want to break the wire).

Filling in wall cavities with sound absorbing materials (accustical fiberglass bats) will do a little.

Point source control (special absorption material) at the source of the sound will also help.

[m Ransley]

Foam transmits certain lower frequency sounds very well, actually accentuating them. I put 2" foam sheet on my exterior, now I can hear the neighbors kids running upstairs ,[ at first I thought it was an animal in the house] houses are separated by 8 ft.

It depends on what frequency you are trying to stop, lower frequencies need more mass as sound waves get longer the lower sound goes. That is why you hear the bass, long waves need mass to be absorbed. It realy depends on the sound-source to be blocked

[Ross Mac]

Maybe not an answer to your question but my house is block construction filled with rebar and cement and it does not block sound well. I can hear the neighbors TV from time to time....Ross

[Ross Mac]

Make that concrete...Ross

[King]

thanks...... I'm still not sure what is better?? Has anybody lived in a townhome without concrete blocks between the units??

[Robatoy]

Te only thing that stops transmitted sound is mass. Plain and simple. The thicker and heavier the better.