Merits of seperate walls to common based walls

I am having a bit of a time informing my Father (a building engineer and contractor) of the merits (transmission loss-wise)of totally seperate nonflankng walls as opposed to staggered stud designs sharing common top / bottom plates. I have downloaded STC charts from the SAE site but it does not list values for Mass air Mass type seperate walls with 2 layers of 5/8 rock. I have searched most of the stickies and many of the Canadian Build links are dead. Can anyone point me to a chart that lists STC ratings for seperate wall designs? I am also having trouble showing facts for justifying double solid doors as opposed to single doors. He is a wonderful but hard headed Dad who has been building and designing for a million years, but I know I can reason with him if I have some printed facts to show him. I know I should be able just to say " do it the way I want" but I see this as a good learning experiance for him as well as good fodder for us to argue together without it being about the family! ;) Tom

IR-761 probably has what you are looking for. It has lots of data for staggered stud configs and double stud and metal stud, etc. Here is a link to the abstract page, the link to the full PDF is on this page. http://irc.nrc-cnrc.gc.ca/fulltext/ir761/ have fun :)

In addition to IR 761 for gypsum walls. have a look at this BBC RD paper for doors. BBC RD 1994/14 Enjoy! Andre