Airspace and Isolation

Ok. I have been learning a lot, but there are some things that I can't find a resource for. I probably am just not looking in the right place, but I'm sure someone here will know how to help me out. This is the situation: Studio will be in a very large building (14,000+ sq ft) but not taking up the entire space. It is a church building and we will be using an undetermined amount of space to build a studio. It is all built on a cement pad. When outside with a train going by (pretty close to train tracks which would be our loudest noise to keep out) we get readings of 120 dB with a bit of snow on the ground. The building is made of solid bricks. We will be either gluing insulation to the brick or building a studded wall and insulating that (with vapor barrier as we get really cold winters). From there, I am trying to figure out how much airspace to put before the studio wall. Not knowing if you consider the insulation as "airspace" I will explain what I call the airspace. What I am calling airspace is the gap from edge of the outside wall insulation to the edge of the inside wall's insulation/floor plate. Also, I've been told that we may not need to float the floor - how can I determine that before building?? Is there any way to figure that out? Should I take readings inside the building at the new studio location to see what the readings are there compared to outside? I am learning as fast as I can, so hopefully these are not too simple of questions. :) Thanks for everything - this forum is my number 1 resource!! Kevin

Kevin, You're talking about needing some serious isolation for the train - and my best guess would be that flanking is going to be an even bigger problem than air-borne noise is once inside the space. The best thing you can do is to hire an acoustician to take some test readings for you - he'll test for airborne and can also use an accelerometer to test the existing slab and structural components. Understand - it isn't as simple as you just adding a floating floor inside of an isolated room to get the benifit of the floor. The floor becomes an integral part of the entire room - and must be a part of the design if it is going to happen in the end........... Sincerely, Rod

Thanks Rod for the advice. I will be searching out an acoustician to help me with those things. The picture attached to this post is something that came to mind while I was browsing some sound proofing websites for ideas. Would anyone care to share their thoughts on this?? Ooops - I forgot to put a comment that the red "globs" were to show insulation. :)

Staggered studs are useless in that context. Before attempting to utilize "soundproofing" construction techniques, it's necessary to understand their purpose so that you can apply them appropriately. Staggered stud construction is a technique used to partially decouple two sides of a single frame wall assembly. It's an inexpensive method that eats onlt 2 inches of floor space and is OK for, perhaps, residential construction where one might want to decrease the noise levels between, for example, a bedroom and a family room. It's a compromise. In your case, your outer leaf appears to be a concrete block wall. By building a frame separate from that wall, you've already decoupled it from the outer leaf (except the floor they share). Staggered studs on the inner frame does you no good. Buy Rod's book... It's in the Sticky threads. --Keith :mrgreen: