Living Room: New Studio in Zagreb, Croatia

Location: Zagreb, Croatia, Europe Hi, I plan to build studio in ground floor of my family house. For now I will call it Living Room and try to build in on concept of living room. The house is connected to other family house. It is situated beside the forest so there is no constant traffic noise. Current SPL in the room is 24.3dB during day. There is some piping going through room and when water running the SPL is 39.4dB. You can also hear when people (children runnig) are using stairs in both houses. Other neighbours are about 30m away. Current situation: Main room dimensions: 880x670x264cm (room isn't 100% rectangular) There is a column in central part of room space (it can't be removed). There is lowered ceiling made of plaster boards and glass wool (ceiling TL 60dB) House connected to another house (wall TL 61dB) There is floated floor. No acoustic treatment: RT60 = about 3sec. SEE PICTURES! WHAT TO BUILD? After year of reading and talking to people I found out that there are many ways to start designing and ever way has it plus and minus. I want to use studio for recording bands (VERY LOUD) and music productions. I can do loud recordings during day time, and quiet during night. One idea is to make one really big live room and use it for recording and mixing after recording is made. I like that idea cause I will use studio primarily for my recordings. Then I can also build one small vocal/drum/amp room. Another idea (3 rooms) is to separate big room in two parts (east and west) and in east part build two rooms: control, and drum/vocal room. South doors would then be out of use. The west part would be big live room with windows. QUESTIONS: What do you think of existing floor? If I build drum/vocal room or controll room on it will it prevent structural noise form outside and loud drum nosie form inside? What do you think of existing ceiling (60dB)? What to do to get bigger TL? If I isolate ceiling and east wall will that prevent noise from studio to house or I need box-in-box? What are acoustic benefits if I build just one big room? Can I use it for vocals? Can I use it for mixing? There are pipes and heaters in the room, part of central heating. Will they transmit too much sound? BUDGET: I plan to use my life savings in it and make it on professional level so buget is no problem. But limit is around 15000$. Thank you. I tried to fallow forum rules, please let me know if I got something wrong.