Capping plaster walls and ceiling?

[Chris J]

Hello soundproofers, was wondering if you could advise me on SPing my plaster walls......after reading about green glue's inability to work with plaster I am now considering capping my bedroom walls and ceiling with MLV and 5/8ths sheetrock.....any thoughts? Also do you think this would help insulate in terms of heat gain and loss? Ripping down all the existing plaster and lath would be a little more than we can handle. Thanks,

Chris

[Randy S]

Chris,
I'm not sure where you heard that from however, to quote "Green Glue must be used as the center of a “sandwich” between two rigid materials. Also, it is a water-based damping material, and it has to dry, so at least one of the materials must be porous to allow water to evaporate."
Therefore, the final layer using 5/8" drywall will work for you! I would add MLV w/psa to the wall first then follow up with the sandwich of green glue and drywall.
It will take longer for curing time but that would be all...

[Chris J]

Thank you Randy, any idea about the insulative value of the MLV w/ 5/8th's sheetrock.....it's an uninsulated 3rd floor room.

Chris

[Randy S]

Chris,
I really couldnt tell you the insulating value all my test data is geared for sound control, if all this is for thermo have you considered blown in insulation?

[Randy S]

This is a blown in cellulose that will address thermo and sound.
http://www.bondedlogic.com/ultratouch-cellulose.htm

[Chris J]

Hi Randy, thanks for the reply.  I would say this is 75% motivated by noise but there is no insulation......Would blown in cellulose address the sound as much as the MLV?  Initially I was thinking green glue but read on this forum that plaster often wasn't flat enough.......Seems to me you'd just use more GG in those area's kinda like laying tile w/ morter. The walls are quite old and ugly so capping them would be a beautification effort as well.

[Randy S]

They are different products, MLV is a barrier , insulation is an absorber....your trying to compare apples to oranges....

basic principles in soundproofing:
1) Decouple from structure
2) add barrier
3) add absorber

I could see this being a problem if the walls are really out of wack...normally a 3 tube formula per 4x8 sheet will fix that.. worst case senario would be having to use dry wall compound to fill low spots.

[Chris J]

Thank you for taking the time Randy!


Chris

[Randy S]

Anytime....