Insolation/Isolation Confusion - Advice Needed!

[dickyd]

It's been a long time since I've posted or even visited to forum! Some serious medical problems sidelined me for a quite a while. Things seem under control now and I'm getting ready to dive back into my project
( http://www.johnlsayers.com/phpBB2/viewt ... highlight=)

I’ve spent a few hours during the last couple of days perusing the forum, trying to catch up with everything I may have missed, new concepts, etc. etc. Following a link (I think from Steve) I ended up stumbling upon this thread in the Studiotips forum: http://forum.studiotips.com/viewtopic.p ... heap+sound.
Reading Brian Dayton's advice and this link as well:
http://www.avsforum.com/avs-vb/showthre ... ost5251072
has led to some confusion regarding the use and performance of mineral rock (specifically Roxul in my particular case) vs. plain ole fluffy fiberglass in floors/walls/ceilings. Help! I'd love it if some of you heavyweights (Steve et al) would weigh in on this one.

If regular fiberglass would work just as well if not better I'd (obviously) love to use it. Saving $$ is a beautiful thing, but sacrificing performance and isolation will cost me considerably more in the end than the dollars I'll save. What do you guys have to say on this matter?

[knightfly]

From all the recent tests of different walls, the general concensus on insulation is that, as far as sound isolation is concerned, the plain ol' fluffy stuff is within a point or two of the "SAFB" products, which are mostly around 2.5 PCF material (usually mineral wool) -

If you run into a code related problem where you need fire stops within double framed walls, a complete fill of mineral wool is acceptable in quite a few locations, but standard "fluffy stuff" isn't AFAIK.

For actual acoustic treatment INSIDE the room, you still need the higher density stuff for best performance... Steve

[giles117]

Even though the fluffy stuff is within a point or two....The fluffy stuff is nowhere near as flame retardant/fire resistant as AFB.

We have MAJOR apartment projects going up in the Detroit area and the Spec is Rockwool in All the walls, exterior and interior.

The ability to conatin a fire inside one area is Rockwools GREATEST attribute and the reason why My Supplier is backordered till Next Tuesday.

IMO, that should be the deciding factor. Safety, not price.

We are designing our new house and that was the #1 requirment I expressed to the buildr. ROCKWOOL everywhere. Protect your investment as best as possible.

Ok enuff of my sales pitch. LOL.

[sharward]

Ditto everything he just said! Amen brother! I've been promoting the use of Thermafiber Sound Attenuation Fire Blankets (SAFB) - Nominal Density (2.5 pcf) and Roxul Acoustical Fire Batt (AFB) - ≥2" (2.5 pcf) for months here for the same reasons you stated.

You probably sold me on it in one of your old posts -- I can't remember that far back!

[giles117]

Ditto everything he just said! Amen brother! I've been promoting the use of Thermafiber Sound Attenuation Fire Blankets (SAFB) - Nominal Density (2.5 pcf) and Roxul Acoustical Fire Batt (AFB) - ?2" (2.5 pcf) for months here for the same reasons you stated.

You probably sold me on it in one of your old posts -- I can't remember that far back!

Totally. I do a demonstration with the pink stuff and AFB with people who ask me to help them get their studios built. I turn on the Burner and put the pink on. I melts/burns

I put the afb on and leave it there for a few minutes it turns red on the ends, then I pick it up with my BARE hand and place it in their hands. They are nervous but blown away that this stuff is barely WARM.

They are then SOLD. LOL

When it comes to Semi Rigid I merely garb the 4.0 PCF (4lb they call it at some places) ROckwool, which is very sturdy. I actually placed it on the walls of my Live room for the absorption. Works GREAT!!!!!