Rehearsal facility in need of HELP!

First off, I just want to say how grateful I am that you guys provide a site like this. I HAVE read Rod's book, and many of the GREAT threads here on John's forum. WOW! Lots of information. Being that this stuff is so counter-intuitive, I think I need some actual real scenario advice. I'll try to be quick and thorough with the details, so sorry in advance if this is hard to follow! With that said, here's what I got..... Question: What type of "common" wall constriction will best suited for this space without using the room inside a room method? We just signed a lease on this 1404 sq ft. light industrial building for use as a 4 room rehearsal complex (See below). It is a small building that was built onto a very large warehouse in which we share a common wall with. We also have two exterior walls facing a retail shop about 20' away. The main common wall of concern has 2x6 plates with 2x6 studs 16" OC. Neither side has sheet rock. Our side (the inner leaf) is a real thin layer of wood siding and our neighbor’s side (outer leaf) is a single sheet of 1/2" plywood with no sheet rock face. The ceiling joists are NOT shared and are 2x10s 24"OC with a 1/2" layer of gypsum board attached. The exterior walls of concern are thin wood/ 2x4 frame/ 5/8 plywood and stucco. We had to sign the lease before doing sound tests, but after sound tests and ripping into this puppy I've confirmed my worst fears! There is major sound bleeding out of this place, both through the common wall and the exterior walls. Right now there is an open floor plan on the south end of the building, where we plan to build 3 rehearsal rooms. The north room is the existing room where we did the sound test. We will be using this room to test our final soundproofing design before continuing construction on the other three rooms. We had hired an acoustics engineer before the lease was signed and he said not to worry about a double frame design. Instead, he recommended we save space by using RSIC-1s w/neoprene and 2-3 layers of 5/8 gypsum using R-19 insulation. He also recommended we "beef up" the 2nd leaf between the studs with Green Glue sandwiched between 2 5/8 gypsum pieces. We are going to use the RSIC-1 on the ceiling joists with a 5/8 of gypsum. Hopefully that will do the trick but we will probably need two layers due to the fact that the joists do touch the common wall. Now I know he is the "sound engineer" but after doing the sound check and hearing how much bleed is spewing out of this place I am having second thoughts whether his design is going to work. Call me a little paranoid, but with $30,000 dollars on the line we can't afford to make the wrong choice. There is one more issue I would like to point out and that is that our door to the north room sits only 3 1/2" from the east wall (one of the exterior walls with bleed). This makes it virtually impossible to have a room within a room without widening the hall and moving the door frame. Our customers will be playing very loud amplified music during regular business hours and into the night. We would definately like contain the sound and minimize bleed. Our main conceern is our neighbors! On a good note, our warehouse neighbor is a Batting cage facility with lots of noise from their end. My business partner is definitely against going with a redesign (room within a room) at this point, so I really would like your honest professional opinion. What should we do!!! Thank you so much for your time! Ben

Ben - that's an interesting problem. I tend toi think that trying to make the external walls work is asking for more problems. You still have to build soundproof dividing walls for each rehearsal room as well. I'd build room within a room like I've drawn. The only additional walls are only thoses running parallel to the outer walls, the other walls have to be built anyway. I'd leave the existing ceiling and walls in the hallways but remopve the existing 1/2" ceiling drywall in the studios only and add a RSIC double layer in each room like I've drawn plus it allows you to extend the fire outlets and lighting. To save space use inside/out walls (check out sideshow's stickey thread) http://www.johnlsayers.com/phpBB2/viewtopic.php?t=6968 That way you cover your internal acoustic treatment at the same time. cheers john

:D John man thanks. That is an awesome design! I was really racking my brain on this decision, knowing that there is really no other way to accomplish this amount of isolation without the famous room within a room. I guess it's back to the architect for a redesign. Better now than after a failed design. Can the beefing up of the outer skin be done from our side of the building(between the studs)? The batting cages have a bunch of gear and funky wall coverings on their side making it hard to add a layer on their side. Thanks again for your expertise John. The engineer we used would have chraged us $2000 to $3000 for that design and it wouldn't have looked nearly as good. Cheers, BEN

yes - you could beef up the walls from the inside as you suggested. The outer walls (east walls) don't need it because of the hallway running down the building. ben - what is a batting cage?? excuse my aussie ignorance ;) cheers john

Batting cages are fenced areas where people can practice hitting baseballs being delivered by a machine. :-)

Yeah it's crazy how busy these batting cages are in our city. There are plenty of little rug-rats running to practice their swing before baseball season starts. Good business! So I have a meeting with our architect tomorrow afternoon to go over the redesign. I have a feeling he is going to ask for specific angles. Should we avoid certain angles or are we in the clear as long as we do not use perpendicular walls? I'm sure I'll be able find it somewhere in these threads, so I'll start looking! Thanks BEN