Can anyone please tell me if there is a difference between Homosote and Soundboard? Some people refer to them differently and some people consider them the same thing.

I have read about installing Soundboard on the floor to prevent sound travel and I am wondering if I can install Homosote on the floor the same way. I have a nice stack of older Homosote, probably made in the 70's, that I would like to put on the floor to cut down on sound travel to the downstairs aptartment. My local lumberyard sells new sheets of Soundboard/Homosote for around $35.00 a sheet. I bought a whole old pile of Homosote 4' x 12' sheets for $20 and am hoping I can use them!!

Any info/advice would be great, thanks.

 

Anyone????

I know there are some of you out there who know the answer to this!!

Please save me from gluing this down on my floor only to find out that it is different!!

 

I don't know that I've ever heard of "soundboard" but there are a plethora of regional differences in what various building materials are referred to. So I'll comment on the homasote.
It is not suitable as part of the floor structure, but if you are going to put it down as an underlayment (an additional layer) and top it with something which is NOT a hard surface, i.e. hardwood, tile, then yes, you can put it down.
Its soft, as you have probably discerned, but under carpet actually fairly comfortable. The downside to the stuff is that it doesnt like water at all. Regular subfloor CDX, OSB, or underlayments can tolerate the occasional spill. Homasote will turn into a sponge pretty readily if you ever get a good spill or leak on it. So I would not use it somewhere that's likely to happen - kitchen, bath.
Other things you might consider, depending on what you have . . .
www.usg.com has pdf files of different wall and ceiling assemblies with STC ratings
if your basement below this floor is open, insulation helps a little. Not a lot, but its so cheap, its worth it.
Principle wise, two keys to stopping sound are mass and isolation. Mass can be almost anything. Additional drywall, your homasote, etc. Isolation is usually achieved through decoupling products. There are products sold in rolls (much like you might use in car doors) but it is fairly pricy. And in the situation where you're finishing an area and have ready access to the framing, using RC-1 which is a metal channel, decouples the drywall from the framing surface. You'll see that at the usg site as well.
Another thing to look for, if you have access, is holes. Mechanicals always run through a hole somewhere, and a little low expansion foam is a great way to seal up gaps where pipes and wires go between floors. Also helps keep the pipes from singing to you as the sink drains.