RC and drywall advice needed

[Greg]

I want to soundproof a wood stud wall on my house that faces a busy road and want to use RC to do so. Since the wall is already built, can I apply the RC directly over the existing interior drywall? Will doing it this way negate the ability of the RC to absorb sound via vibration? Or is it best to remove the existing drywall and apply it to the studwall then re-drywall the interior. Please advise. Thank you for you help.

[Randy - Super Soundproofing CO]

: I want to soundproof a wood stud wall on my house that faces a busy road and want to use RC to do so. Since the wall is already built, can I apply the RC directly over the existing interior drywall? Will doing it this way negate the ability of the RC to absorb sound via vibration? Or is it best to remove the existing drywall and apply it to the studwall then re-drywall the interior. Please advise. Thank you for you help.
The reason you may want to remove the drywal is to lay in absorbent matting inside the wall and also to increase the size of the dead-air space.  These are both very desireable things to do and would recommend you do this.  If this is not done, it's not the end of the world, but will make for a much better, effective job.  If you don't do this at least increase the size of the air-space you are making by using spacer blocks (furring strips) to bring out your new wall as much as practical.  Line the old wall and the new wall with thin absorbent mat to create a soft compartment to absorb sound and to dampen the wall structure.  Read about this at this link and call if you have any questions!

• Soundproofing existing wall