Ceiling Construction Choices

Looks like I have a choice to either frame a new ceiling connected to the new inside walls being built or suspend it from the existing 2x12" ceiling/floor joists from the second floor above. Not sure about which type of ceiling hanger to use to support the ceiling framing and 2 or 3 sheets of gypsum or what the tradeoffs might be with STC ratings. Any info appreciated.

Whoa! Your first question about MDF was specific enough in scope that it could be answered. What you are now asking cannot be answered simply. Read and follow the second announcement at the top of this forum. Andre

Sorry, you're right, I was being pretty vague. I guess I'm just trying to find out some general opinions and info about ceiling designs. I've always constructed ceilings tied in to my new "room in a room" walls and have always tried to have zero mechanical connections to the outer structure. Poking around the site as I have the last few days I've noticed quite a few ceiling designs where people are using several different types of acoustic designed hangers to attach the inner ceiling to the existing ceiling or ceiling joists. While I can't think this would improve STC figures, it could possibly gain a few inches of ceiling height which would be important in my situation. I only have 9' 11' from existing floor to the bottom of the second story floor joists. So still getting my feet wet around here with protocol, but was curious in general if given the same layered coverings (GB x 3) can a ceiling suspended from the existing structures ceiling or joists perform as well as one completely isolated? I promise my future questions will definitely get much more specific (probably ad nauseum lol) as I get my design plans together. Build begins Jan 1!

I am struggling with this same choice right now. Im going to build a room within a room, but haven't decided on the ceiling. The ceiling will be either: 1. hanging off of the bottom of the truss ceiling joists, but isolated from them using RSIC type clips with hat channel. This would be cheaper, easier, and allow for more ceiling height. But what is the cost in STC? or 2. Hanging off of joists sitting on the inner walls. This will cost more and reduce the ceiling height. How much will this improve the STC? Is it worth the cost and and loss of height? Does anyone have any advice or experience in this tradeoff decision? Thanks!

I don't see how ceiling height is affected.

Specialkm: Either delay your build start by several months to start to get a proper design or pay for time of a studio designer to design your studio. Make the decision quickly as you want design work done over the holiday season. You read the announcement, yet did answer significant questions relating to your question, much less any of the rest of them. You will have to answer those questions here or to the paid designer.. Just three examples of what is needed for some of a valid answer to your ceiling question are: how much isolation do you need? What will the new walls be made of? Can they support the weight of the ceiling? What are the current walls made of? What is the span of the room? What is the current construction of the ceiling? This is just a fraction of the information needed to give useful advice. Andre

"So still getting my feet wet around here with protocol, but was curious in general if given the same layered coverings (GB x 3) can a ceiling suspended from the existing structures ceiling or joists perform as well as one completely isolated? You suggest that this is not only your first time but that you "always" do this or that. Which brings me to another question. Assuming that you have designed/built other structures, I wonder why an STC point system is still on the tip of your tongue? To answer your question. The short answer is No. The long answer is based on how you answer this: "I've noticed quite a few ceiling designs where people are using several different types of acoustic designed hangers to attach the inner ceiling to the existing ceiling or ceiling joists." Where are those people...show us the links to the build. To echo Andre: "This is just a fraction of the information needed to give useful advice." Anytime, and I mean anytime you attempt to attach something to the underside of an overhead system, you are messing with danger. All it takes is you overloading the dead load of the overhead floor system with your X3 sheetrock plus the additional live load and you can kiss you ax good bye :) Not enough information, too much bravado.

Well, best sounds like I should abandon this topic in so general of a manner. I only posed the question in such a non specific way because I was just looking for a non specific comment such as "In most situations a completely isolated ceiling will offer better isolation than one suspended from the existing outside structure with acoustic designed hangers". This would help validate my own thoughts on the subject and help narrow down some of my options in forming my plans. There weren't many of these types of hangers available the last time I put a room together so I was curious as to their implementation and advantages/disadvantages. In looking at some of the specs and pricing of these products, hanging the ceiling doesn't really appear to offer any advantages in my situation. I don't believe it will offer any increased ceiling height (may actually decrease it with some of the hangers) and I believe it would also be more costly than framing a ceiling on top of the new walls. Thanks for the comments and your patience. I'll be very specific in my next threads.

In general terms, a ceiling that is framed with new joists which are hung on the newly framed inner walls is best. This creates a complete room within a room. This is a decoupled assembly. Improvements to low frequency performance come from adding (not stuffing) insulation, mass from 5/8" drywall, and increased air cavity depth.