concrete floor

My design is not finished, my sketchups are bad but I work ! see http://johnlsayers.com/phpBB2/viewtopic ... 3&start=30 I ve red rod gervais ' s book & posts. I don t want a floating floor in the studio, just put some wood screwed to the concrete. But before the beginning of the studio, I need to begin a building demolition in a month. The studio & the building to be demolished & neighbour are on the same concrete floor (see jpg). Do you think I need a "saignée" ( maybe Groove in english ?) in the concrete? cut the concrete between studio and where cars will drive to avoid sound & vibrations ( blue think in the jpg) do you think I need to do the same stuff between studio & neighbour ( red think in the jpg ) ?

Hi garlo, I do not think you want to cut the concrete. Cutting the concrete will weaken it on the edge of the cut. --Keith :mrgreen:

Hi Sharward I don t want to cut the concrete, I want to know if I need to cut it ?

Since the concrete is on the ground, and the ground acts to dampen the concrete, I don't think the concrete is an effective transmission path. I have learned a lot about this over the last two years. If you had asked me two years ago, I'd have given you a different answer. ;-) --Keith :mrgreen:

Thanks very much

I'm not that certain this is true - the best way to know if you need to cut your slab (and if you do, you'll need to do a LOT more than just cut it, you'll need to cut a section out and pour a new footing) is to lay down on the concrete at the neighbor's area, and put your ear against the concrete - then have a helper bang on the concrete where your studio will go with a hammer - preferably use TWO types of hammer, one a normal metal one and the other a rubber hammer. If you hear the hammer loud and clear, then whatever is beneath the slab is NOT damping the concrete enough, and your neighbor will NOT be happy with your studio unless he/she LOVES your music.... Steve

Sorry... I misread the original question. I now see the two lines. I wasn't able to see them before (darned PDA screen). --Keith :mrgreen:

Hi, ok i vemade the test... I can hear the hammer loud & clear coming from the north wall but I can also feel the sound coming through the concrete. That building was a printing company ( with big Heidelberg printing machines). I suppose the concrete is like in my house ( the building on the west side), 20cm thick. So do you think I need to cut it maybe on 20cm large, & add some styrofoam or polystyrene before new concrete as : old concrete neighbour / styrofoam / new concrete/styrofoam/ old concrete studio. ?

Rod's book includes details on how you can cut concrete and then reinforce it from underneath so that it won't be weakened by the cut. It's definitely a lot of work, but in your case, it may make sense. --Keith :mrgreen:

Agreed. You absolutely cannot go wrong getting that book, it'll be the best $ you spend... Steve

I have the book, I red it again. Great book, thanks Mr Gervais. Do you think it s better 1 /to make a new concrete floating floor inside the studio on the existing concrete or 2/ to cut the existing concrete outside the studio and make a new one 20cm large. Both 1&2 can be made according to Rod's advices.

What's the status of the space right now - is it just a slab with all walls down, partially demolished, or what? What's your budget, and what is included in it? How loud are you/will you be? How loud is the neighborhood? What's your timetable? Do you have a tentative layout design, and if so where's it posted? Any other answers we've not asked the questions for, feel free to share - the more info we have on your situation, the closer to reality we may get with suggestions... Steve

Im a composer and already running a small studio. http://www.cipaudio.com/eng_studio.htm I work mainly on my music + sound design & music for cartoons, movies, tv & radio ads & some music mix & mastering. Very few live recordings. Our vocal booth is actually the main recording room. Our control room is about 40m2. One year ago, I transformed an old industrial building in the suburb into a home & 2 appartments. Project I would like to design and begin my new studio near my home that year. First I need to demolish the east part of the existing building so cars can go from the street to the new parking on the North,make new roofings, make a small house for a friend on the northern part of the building. Space After that I will begin the studio. It was a printing company before. The space is 9m38x7m38 inside. The height in the center (line East to West )is 4m22, and 3m30 on the North & South walls. Floor is concrete (20cm, same as the floor of the east part building I will demolish , & same as north part where there will be neighbourhood). Walls are hollowed bricks (hollowed stone walls?). Roof is metal ( steel?). There will be a joint(?)neighbour on the north (second problem). Other neighbours are on the west side, me, & 2 on the 2nd floor of my house, other houses are 50 meters away on the Eastern side. Use Sound design for commercials , multimedia ... Music composition, mix & mastering ... & maybe some live recording ? So usually many people in the control room (too much). I ve tried a CR of 6m x 5m. We need a vocal booth ( 1 or 2 speakers & a tv screen). We need some windows on the South. A door on the North for people coming from the parking. A big door on the Eastside for loading unloading musicians gear. A small room with the computers & amplifiers & adat will be great ( sound lock ?). A live room will be great. Here the last idea : http://www.johnlsayers.com/phpBB2/viewt ... 9eb8d0acc9 I ve tried to put the CR far from the North wall. Gear I will moove the existing gear so Protools digo02, Adat , Mackie d8b,Weiss equalizer, Tc electronic finalizer & reverb, Lexicon reverb, NS10 & Adat monitor II with Alesis matica900 amplifier, Neumann Akg Audio technica microphones... Loud Sorry don t have something to measure, but when its loud its just for few moments in the CR with Adat monitor II + amplifier matica900 when mastering techno or dub music. The main business is made with the NS10. Even if we try in the future to work in the studio on live recording, it will be choirs or some bands with drums , ( hard rock bands use to work in another studio). Budget I will try with 20.000US$ for east part demolition, new roofing ( cheapest in france is sandwich-steel as on my house), friend house. work on the concrete floor. and 20.000US$ for the studio itself. Timetable I must demolish the east part & make new roofing before summer (building licence). I will try to open the new studio at the end of 2007.

What do you think ?

? please forgive my bad english , just want to know what do you think the best solution with my concrete floor ?

Think I will try witha floating concrete floor for the CR.

I'm sorry that your thread seems to have "died" on our end, garlo. :oops: You've done everything we've asked of you, and yet we neglected to give you a definitive answer. :( My original thought was that you wouldn't have to worry much about it, given that you're "slab on grade." However, after I wrote that, there was an intelligent challenge to my statement. I personally still don't think you need to do anything too drastic, but that's just my instinct. I would hate to steer you wrongly and have you end up in trouble because of actually following my guidance. :roll: I'm really not as informed and experienced in this as it might seem at times... ;-) Right around the same time that your thread started, I wrote "Is a Floating Floor Right For You? Answer: Probably NOT" in an effort to help reduce the floating floor question/assumption madness around here. I still stand by that thread/article and its assertions, especially having had a number of experts around here weigh in and/or give me their proverbial "stamp of approval." If you have not reviewed that thread, please do. Have you purchased Rod's book yet? He covers the "to float or not to float" question pretty well in the book. If after weighing all the evidence you decide you're going to more forward with floating a concrete slab, please educate yourself thoroughly on this subject and get some professional consultation for the calculations that are necessary in order to have an outcome that is not worse than if you had not floated. (Is that enough bold print for you? ;-)) --Keith :mrgreen:

I havent read that thread before. Thanks very much. I was confused, i m now very confused, completly lost. my last project is there http://www.johnlsayers.com/phpBB2/viewt ... 3&start=30 don t know what to do

Hey garlo, In a way, I'm sorry that I have left you confused. And in a way, I'm not... Because confusion leads to stoppage, and that's what you should do until you're 100% sure how to proceed. :-) Perhaps some others will weigh in on this critical decision point for you. Can you post some photographs of your property? That may help us all better understand your situation. Hang in there... We're here to help... And sometimes confuse. ;-) --Keith :mrgreen:

Ok you right thanks Sherward.

Thanks for the pictures. 8) Well done. :-) Now, how about that street that we can't see? Is it a rural 2-lane road with very little traffic, or an 8 lane main thoroughfare with a lots of traffic, including large tractor-trailor trucks that rattle the entire building, or something in between? :roll: And is there a train track on the other side of it or anywhere nearby? I actually think that these arethe questions that will dictate whether or not engineering a floating slab is even worth thinking about. --Keith :mrgreen:

Its a 2 lane road ; a typical suburb main road, with suburb trafic, people goin to work downtown from 7to 9am, & coming back from 5 to 8 pm. not many trucks & tractors, some buses. No train tracks, but airport is 4kms NE I can t hear the road trafic nor planes from my home. home is made with the same walls - hollowed bricks, I added 10cm rockwool & 1 leave of13mm plaster ( I know now thats a 3rd leaves wall, but i made it before). So outside sound is not a problem. Sometimes in summer time when we are outside in the garden we don t hear traffic but hahaha ... lions !! There s a zoo 2kms NE. But no lion sound inside !! I m more anxious with neighbour behind the Northern wall of the studio (thats why my project is now based on a CR on the SouthWest part of the building), but on the same concrete floor.

Honestly, I'm thinking that you probably do not need to worry about the shared slab being a significant structure-borne flanking source of airborne sound. We've seen hammer tests before, but they really don't apply in my opinion because a hammer strike is impact noise which is entirely different. Think: knocking on a door is going to be a lot louder to the occupants of a house than an airborne sound of equal intensity. Also, hollow concrete block walls are not two leaf as previously thought. They are considered as one leaf. Filled concrete block walls are in fact better because they're heavier and more massive. --Keith :mrgreen:

Thanks very much Sharward or Keith ?? So i leave the concrete floor. Maybe just add a floating floor with wood & sand in the CR ( not for the sound but for the design & cables ) ?? ----- For the walls you say that hollowed concrete blocks are considered as a 1 leaf ?? So maybe I can add "carreaux de platre" (660MMX500MMX100MM = 100Kgs / M2 see picture http://www.johnlsayers.com/phpBB2/viewt ... c&start=15 to add more mass, and then CR & live area touching the walls ?? Thats from inside to outside : 13MM plaster/ Green Glue / 18mm plaster / 100mm Rockwool & steel framing / 50MM air / 100MM Carreaux de platre / existing hollowed concrete blocks 200MM. ??

and ?