Building new facility - Area is half concrete / half wood

Hello there, I've been looking through the site for many months now and finally decided to sign up. I read the book (Recording Studio Design and Construction) and have come away with one question on what to do w/ my new place... I have purchased a general store building from the late 1800's that was not well taken care of. After a few years of renovation, I have made the front part of the building with the original tin ceilings into a live / work space (this has a crawl space underneath it). In the back there are two different areas that I am building the studio in. They consists of two 20 X 20 foot rooms (approx 400 sq feet and both have 11.5 foot ceiling) that are separated by a brick wall. One of the areas rests upon the 20 X 20 basement area which contains my furnace, hot water heater, plumbing access, etc. The is reached via a trap door in the floor. With this being said, I have concerns with pouring concrete or using sand in this area for two reasons: 1. I have had two contractors (one I trust with my life) tell me that since the building is so old and although we have leveled the area out, added support, etc might be at risk for having that much weight put on it. I could do the floating floor, walls, ceiling, and proper amount of RC and drywall though, but adding more to that could be bad for such an old structure. All I keep reading is now to NOT do this, but what if you have no choice - if you can't do sand or concrete because of weight? Onto the far back area. This was a newer (maybe 60 years ago) addition that has a poured concrete floor - straight to the earth. This is clearly a much easier room to do any "proper" work in. My big question is - which area do I use for what (if not able to use sand or concrete)? Is the area with the concrete floor the control room, or made into a tracking room? With past clientele, I'm very split on the amount of tracking and mixing work I do, and don't want to sacrifice either. Any thoughts on what else can be done in the "basement" area? I've budgeted for insulation, neoprene, and double layer of flooring - but is there some other sort of floor material that could help the low frequency area of this space? I'm very worried that the between the hollow floor and basement beneath is, I may have some horrible low end to deal with. But what would be worse, dealing with this for tracking a drum it, or mixing... I would assume mixing, but... One last item to consider: the concrete portion has the door which leads to the load in and parking area. This makes me want to use it for tracking room with the ease of getting bands in / out. Thanks for the help and I've attached a very simple drawing of the space. Brian

i think you have it right - use the easy access solid floor for the live room.

Hey Glenn, Thanks for the input. Any thoughts for the room in a room design for the control room (the wood floor area that's over the basement in the 100 + year old part of the building)? I have no neighbors in the front or back, and the entire building is mine, BUT I do have a building on either side of me. One is a warehouse that my family owns and noise isn't currently an issue (as long as it's not sold) and a rental business space on the other that contains a heating / cooling contractor (who doesn't care about noise, but this could obviously become a restaurant, etc some day, and I want to cover my ass). So, building out the live room in the back isn't an issue (with the concrete floor to the earth and all), but I worry about how to build the control room without doing sand in the floors or concrete... Is there truly no way to make a floating floor / wall / ceiling system work with just doing insulation and two or three layers of flooring? If this is just a project / songwriter studio and no major albums are going to be cut here (I just want to reduce control room sound to neighbors and get decent mixes) will I really come out with horrible mixes? I just feel as though people here are a bit over the top for the kind of records they'll be making and how little money they'll get paid. Don't get me wrong, I like doing things the right way, but for structural and budget reasons - I simply can't make the proper way work out. Just my two cents... I've attached a picture of the building front and bits of the adjoining units. The store front part of the building is my office, lounge, bathroom, etc. Studio will be in the back away from the street. Thanks again Brian