Concrete floor, 1st floor. What to do?

Hi, hope you're all doin' fine. I posted here a while back while renovating my control room and enjoyed all suggestions and advice of this funny community. After opening (or should I say reopening) my studio to clients I'm back in full force and am enjoying every minute of it, been recording a lot of music and the business is doin' mildly good. I'll get straight to the point. I might be able to build a new recording studio before the end of the year, into new premises, a lovely space that will house both my home and the studio. The building is made (as usual here around) of reinforced concrete with pillars all around. The studio space is on first floor (it is street level but there's a basement down under so...) and the house is on top of the studio. Floor space (including entry, lounge, storage and bathroom) is around 130sqm. Right now the space is used as offices and light industrial works. Overall height all around is 3.5m, a big departure from the typical 2.7m you get in house in this part of the world (and what I got in my studio right now). I plan to leave the entry (to be lounge), storage and bathroom untouched (to cut down on costs). For months I read books (Rod Gervais') and forums, tried to grasp as much knowledge as possible, contacted studio designers, exchanged e-mails, worked with sketchup to see what I could fit and I could not, and here I am again asking for advices and suggestions. I read the "Before you post" so I'll try and do my bestto fill in as much info as possible. Here we go: Actual: The building sits in a private owned land right in the middle of an industrial area. There is another building right beside it (directly connected). All other factories are spread around all sides and they do have working hours of 8-5 or so. There are just a couple houses nearby (most notably mine that would be on top of the studio). The building is around 400sqm but space for the studio will be much less, with the remaining to be used as offices. It has its own entry, and stairs that brings you to the upper level. Overall height is 3.5m. Attached a drawing of the bare bone space and one with the studio space outlined to give a better idea. (EDIT: decided to put up the sketchup file too just because it seems most of forumers here use the software and know their way around it). Where am I right now? Where am I? Well, I'm planning, sleeping less and less and dreaming. I'm still tryin' to figure out if it is at all possible to build something comfortable to work in in this specific place. Have to tell you that this might be the last time for me, don't think I'll get another chance in the near future to build something like this and coming from the very bad experience with my actual studio (especially regarding isolation) I'd like to hit the target once for all this time. What do I do? I do record music. Rock music, folk music, drumkits, guitar and bass amplifiers, mostly live but do overdub a few things here and there (acoustic guitars, percussions, vocals, keys, piano, organ, strings, brass...). Most of the band I work with are on the loud side of things but not like "20000W PA blasting in fron of you" side. I worked with very few metal (or heavier) bands in the past, but my core business is what I call "straight rock", very simple lineups, drums-bass-guitars-vocals, ranging from acoustic to electric and in between. My client base is made of non professional musicians for the most part and hence I work mostly at night and on weekends, usually wrapping the session up at around 11PM. My setup is fairly simple. A big analog desk, a DAW, a few outboard processors (comps mostly, mic preamps, eqs), two sets of monitors and a few musical instruments (two drumkits, 5 guitar amps, a dozen guitars and basses, some other assorted crap). What I'd like to get? I'd like to have a recording studio with a spacious control room, able to accomodate 5 people (that is me and the 4 band members, 99% of the time), a spacious tracking room with space for a complete drumkit and a small iso booth to be used for various duties (amp room while tracking rythm session live, vocal room for overdubs, piano room etc.) I'd like to be able to work at my hours, without annoyin' my family (wife and kids) and without outside noise driving me mad. I'd like to leave the lounge, storage and bathroom untouched as much as possible. I'd like to have direct access to the booth or the tracking room without walking to the lounge everytime. I'd like to have direct access to the bathroom without stopping the sessions, that means being able to take a piss and not having to walk down the middle of the tracking room to get there. I'd like to leave access to stair untouched in order to have a private access to my house without having to go outsides and up the external stairs. EDIT: Forgot to include budget. What about 20k euros? Please keep in mind that I have a few friend (contractors) that can help me out. So, hope I put down as much details as needed. Here are the drawings (or file). Please feel free to throw anything at me. Cheers, Ronnie

In the meantime, here are the two ideas I came up with. Forgot to tell you that I'd like to hire a studio designer to put down all the fine details, but I'd like to get as many inputs as possible from the forum readers.

Here is another idea I came up with, borrowing the control room design from a forum member (Glenn). Had to move the lounge area wall a bit to the left. Created a soundlock on the right and a machine room/storage/whatever down in the bottom right corner. No acustic treatment in the drawing, I'm fully aware of it. EDIT: No booth, I couldn't make it fit.

Hi Judah. To me it looks like you are wasting space with that sound lock. I think there is a way to get a bigger control room and maybe also a small booth, but I don't have time to play around with your SketchUp right now. the basic idea is to put the control room where the live room is right now, but rotated 90 degrees, then put the live room alongside, with access through sliding glass doors, to save swing-space. If I have a chance later, I'll see if I can outline what I have in mind, for you to play with further. Those pillars sure are a pain! - Stuart -

Soundman2020 wrote:

Hi Judah. To me it looks like you are wasting space with that sound lock. I think there is a way to get a bigger control room and maybe also a small booth, but I don't have time to play around with your SketchUp right now. the basic idea is to put the control room where the live room is right now, but rotated 90 degrees, then put the live room alongside, with access through sliding glass doors, to save swing-space. If I have a chance later, I'll see if I can outline what I have in mind, for you to play with further. Those pillars sure are a pain! - Stuart -

Thanks Stuart, yeah those pillars sure are a pain but I'm used to them by now, had to design around them for years, since I built my first studio. Thanks for your help too, I'll try and develop an idea along your guidelines and will look forward for your sketchup if and when you have time.

Hi Judah, I was just looking at your SketchUp file, and trying to insert some ideas, and I could not figure out why it looked so weird and small. Until I noticed that your model is not drawn to scale!!!! your walls are 3.5 meters high, some of your doorways are 3.2 meters high! Some are taller than others, and they don't match up with the window lines. Some are wide, others narrow... If you fix your model (make everything accurate and to scale) and re-post it here, then I'll have another try. - Stuart -

Sorry to disappoint you Stuart but the sketchup file is perfectly to scale. I drew it with the original drawing in the background. The doors are in fact 3.2m high, doors with windows on top, the door in itslef is 2.2 but then there's a glass over it. The windows are not all the same, hence why some of them are narrow and some are wide.

"and coming from the very bad experience with my actual studio (especially regarding isolation) I'd like to hit the target once for all this time." Then you should remove the overhead windows. I realize it is a common thing to do this to allow air access in and out of the rooms in a residential environment, but it is not helping your isolation.

Spoke with my uncle this morning, he's the structural engineer who designed the building. The concrete floor should handle weights in the neighborhood of 800Kg/sqm, he's gonna look at the drawings but told me that we should be around that figure.

Ok, here's an updated SKP file with all windows and doors with correct dimensions. The red area is the one devoted to the studio. I took one wall down to see if it gets any easier. Anyone's willing to give it a try? Thanks. EDIT:: put a file image too to give a immediate input

xSpace wrote:

"and coming from the very bad experience with my actual studio (especially regarding isolation) I'd like to hit the target once for all this time." Then you should remove the overhead windows. I realize it is a common thing to do this to allow air access in and out of the rooms in a residential environment, but it is not helping your isolation.

Thanks xSpace for your input. There's only one door with overhead glass, and that is the entry door.

BTW, speaking with my uncle I discovered that the concrete floor is 10 inches thick (25cm). I still don't know wether I should float the rooms or not, even if I know that as it is right now (same building structure as I have now) is very poor in isolation. I suspect that the problem in my studio is about flanking both in the floor and the ceiling (both concrete, both common to studio and house). I read a few pages off of Philip Newell's book and saw some very interesting data about floating floor materials, including rockwool. At the same time discovered a thread on Gearslutz about the very same matter with some input from Rod Gervais and he mentioned using rockwool to float rooms in some specific cases: An good example of this arouse out of a professional grade mixing room I designed in Brooklyn NY - which is located on the 1st floor of one of the old "Brownstone" buildings there. Due to it's location in a residential neighborhood - and the owner's need to be able to work any time of day or night - I went to some extraordinary lengths to make certain this worked. The walls and ceilings are floating - but the structural wood framing for the first floor deck was incapable of carrying a separate isolated slab. Now - granted a few items which pointed me in the direction I headed: 1. this is a mixing room - and the owner is mixing around 85 dB - so it isn't as if I was recording a band operating around 110 - to 115 dB. 2. The owner is NOT mixing music utilizing subs as a part of the package. 3. The deck assembly is carried by a brick wall which is also the party wall between the 2 units. I was able to add plenty of mass to separate the deck assembly from the basement beneath it (where the Owner hopes to "one-day" install a drum room). So my largest potential problem was not air-borne sound making passage - but rather flanking noise transmitting through the deck structure itself. I settled on 2" of 703 with a double layer of 1/2" plywood over that - GG and lapped joints - with 1 3/4" screws to attach the 2 sheets together without penetrating the insulation deep enough to short out to the floor below. One note - 705 is much too rigid to make work with this arrangement - it has a capacity of 100 psf live/dead load - and the numbers really have to be around 40 psf ll/dl combined for this to work. It worked perfectly. Here is the GS thread in case: http://www.gearslutz.com/board/studio-building-acoustics/369515-poor-mans-floating-floor.html

I think you should read this carefully: FLOATING FLOORS: viewtopic.php?f=2&t=8173 It's not clear from the citation you posted above, but I suspect that Rod was not talking about floating a floor on top of a ten-inch concrete slab! A ten inch concrete slab is about as good as you could hope for, in terms of isolation. It doesn't get much better than that. Floating a floor is not something you do lightly (see the above link). Getting it right is really hard, getting it wrong is dead easy, and getting it wrong will most likely make things WORSE than if you had not floated it at all. There are just too many things that you have to get right in both the design (calculations) and the construction. Get one single item wrong, and the floor will be a flop. If you DO decide to do it, then you should probably consider paying someone who does know how to do it right and has done it successfully before, such as John or Rod. The total budget you mentioned is probably nowhere near enough to include float your floor properly anyway. - Stuart -

Thanks Stuart. I have yet to understand if concrete slab are any good for isolation or not. In my actual studio I have a continuos concrete slab shared by the house and the studio (and the ceiling is just about the same). Got double walls between the two and when I have drummer in there recording it sounds very very loud in the house too, even in bedrooms that sit on the other part of the building (where talkin' some 15m away from the studio). Is it all about flankin? PS: I also understand that you do not need to float a floor if you got concrete slab in a basement, that means your slab sourrounded by hearth. My wanne-be studio space has a basement down under, no hearth whatsoever around the 10inches slab.

I'm tryin' to get a grasp here so if anyone is willing to help I'd much appreciate it. Here's the only scientific data I could find about concrete slab. http://www.kineticsnoise.com/arch/tests/pdf/B10.pdf It looks like my 10" concrete slab has some respectable (to say the least) isolation figures (the 6" one rates at 39db@50Hz). I still don't understand where all the noise would come thru then. I mean, I've been living in concrete buildings for all of my life and working in a recording studio built into a concrete building for 10 years and allways thought that some sort of magig voodoo was needed in order to get any kind of isolation, bacause I can tell you that my studio right now suck quite badly. Just an example (apart from the noise in the house that I explained a couple post above), if I have a drummer playin in the recording room I can feel the kick drum right in my feet while sitting at the console. There are two thick brick walls between me and the drums btw. Back to my design: Will I have to build the walls right on top of my concrete slab (BTW, there are ceramic tiles right now), put a ceiling on top of'em, make the structure airtight and press record? No sound will travel thru the slab and into the entire structure (remember that there will be my house on the floor above)? I'm puzzled. Please help.

I think you might be confusing "isolation", "decoupling" and "flanking". A 10 inch concrete slab is a pretty good isolator for airborne sound between rooms: It has lots of mass, stiffness and density, so it will stop airborne vibrations very well. But concrete also transmits impact vibrations well. In other words, if you stand in front of a concrete wall and hammer a nail into a piece of wood in mid-air, without actually touching the wall, then that sound will not make it through the wall, since it is airborne. But if you put the piece of wood up against the wall and hammer the nail in, that sound WILL get through very well, since it is coupled directly to the wall. It is impact noise, and the wall transmits its easily. If you build another wall just beyond the first one, the sound of the hammered-nail-against-the-wall will NOT get through the second wall, for the same reason as in the first case: the sound is airborne, so the wall stops it. And the huge impedance mismatch between the air and the leaves on both sides and in the gap, plus the mass, rigidity, density, damping,etc. means that the sound in the air does not "get through" the wall easily. HOWEVER: neither of those discussions deals with the issue of flanking. Flanking is sound that gets around your isolation. It takes another path, detouring around the air gap, not through it. So if there is a steel bar connecting the two walls in the above example, that is a flanking path, and the vibration in the first wall is transmitted directly to the second wall, regardless of the air gap. Ditto if you have both walls directly attached to the same floor. Something else is transmitting the sound directly, mechanically, from wall to wall, "bypassing" your air gap. In order to stop flanking noise getting around the walls, you have to decouple in some way. Either you do something to disconnect one or both of the walls from the floor (such as mounting them on a decoupled, resilient platform of some kind), or you move the hammer-and-wood away from the first wall, so that they never actually touch it, and you only have airborne sound again, no direct impact. In the case of a drum kit, a good drum riser will help decouple the kit from the floor. Does your current studio have a well designed drum riser? That might be the problem. Or maybe the walls just are not up to par, and the drum sound is getting through anyway. In the case of your second-floor studio build, just relying on a single concrete floor is not going to solve the issue, no matter how well it isolates, since it is only ONE leaf, and it is still coupled to the building structure. Like several people here already said, since floating a floor is probably not an option, the only other option you have is to treat the ceilings in the rooms below, to decouple those from the slab. Remove the existing ceilings, and either use RSIC clips and hat channel direct on the underside of the slab, or resilient channel on existing joists, or a completely new set of joists that are NOT coupled to the building structure, to hang your new ceilings. Then add at least 2 layers of 5/8 drywall with Green Glue in between, and acoustic caulk in the small gap around the edges. That will take care of the flanking, and will also improve isolation greatly, since it adds a second leaf. And if flanking is still an issue after that, then you will have to do the same on the walls in the rooms below: add a second set of decoupled walls to the rooms below. Perhaps with RSIC clips on the walls and hat channel + drywall, or RC on the studs (if there are any), or new separate studs, plus a couple of layers of drywall with GG. Just like the ceiling. As far as I can see, this is the easiest and cheapest way of dealing with the issue. Floating your entire second floor (or at least the studio part) would be the other option, but it will be prohibitively expensive, as it involves many tons of concrete that is cast within a new sub-floor framework that is attached to decoupled screw-jacks on isolation mounts, that are raised once the concrete is set. And the existing structure most likely cannot take the huge additional load anyway, so you'll have to build additional pillars to support that, etc, etc. It can be done, but not easily and cheaply, like just hanging new ceilings downstairs can be done! The simplest, least expensive approach is to isolate the rooms on the first floor, as far as I can see. There just isn't an easier way to do what you want, since the laws of physics apply to your building in the exact same way that they apply to every other building. You can't wish them away. IMHO. YMMV. - Stuart -

"In my actual studio I have a continuos concrete slab shared by the house and the studio (and the ceiling is just about the same). Got double walls between the two and when I have drummer in there recording it sounds very very loud in the house too, even in bedrooms that sit on the other part of the building (where talkin' some 15m away from the studio)." What are the chances that the walls are all the same height and that sound is jumping over this boundary? That is what it reads like to me. Your ceiling is the weak area, currently, allowing airborne sound to move around between rooms. Got pix :)

Thanks Stuart for your detailed reply. I really appreciate your help. Regarding my actual studio, there is absolutely nothing I can do to improve isolation in the floor below me. It is a 400sqm factory with no partition wall, no ceiling, no stud. Just a bare space that shares the ceiling with my floor (same concrete slab, with a tad of plaster down under) and that is it. xSpace, attached is a drawing that sort of explains the studio construction. Unfortunately I don't have all the fine details (don't have any picture of the building during costruction) but this should be it as far as I remember. I was young and stupid and thought that 2 massive brick walls would have stopped every kinda of sounds. That was (and is) not the case. BTW, in the new spot I have a concrete slab 10" thick that can handles more than 800Kg/sqm. I also perfectly understand that flanking is a huge issue with concrete building, that's why I asked for a floating floor. Last night I was thinkin' that maybe floating only the tracking room would be enough. PS: the old studio (where I do work everyday) needs to be forget. Demolishing it and rebuilding it would be expensive, at least as much as building a new facility as I outlined in my first post. Other drawbacks: it is on a second floor, so clients need to bring instruments up a flight of stairs everytime (and there's no cover for rain, very annoying). It is 2.7m from floor to ceiling and I would like a higher ceiling to work with (at least in the tracking room). The new spot is a bit taller (3.5m), it is on street floor with easy access and a bit of parking in front of it. And I can start from scratch with a bathroom already in place, lounge and entry, storage space (I have basically none right now and my tracking room is full of instruments, list as off last night: 2 drum kits, a dozen guitars, 7 guitar cabinets, 5 guitar amps (head or combo), 3 bass amps etc etc..)

A quick update, I contacted John and am waiting a reply on a few basic points before commiting.

"(BTW, there are ceramic tiles right now)," Based only on my thoughts about ceramic tile and those that install it, this would be a bridge from room-to-room or wall-to-wall, worse then the concrete would be. IF the tile did not crack from nails being driven into the bottom plates or simply the weight of your build, either one is inevitable.

I contacted John ...

Smart move!