New Design - Small post production studio in old apartment

Hello everybody, I've been reading topics here for months already, and I must admit that this forum is a wonderful source of informations. A big thanks to everybody here for discussing topics with conscientiousness and good mood. Anyway today I'm embarking on my own project which is a small post production studio located in one of the bedrooms of an old apartment close to Paris, France. Situation and conditions are far from being ideal to build a studio : - It's small : 14,5 m2, - The building is old (1895) and not very well isolated, - The apartment is located on the first floor, so there is neighbors below and above my apartment. BUT, there are still some good points (well, I hope these are good points): - As an old building, walls are thick! (between 30cm and 60cm for the outside one), - Although 2,75m of ceiling height is not much, I still feel lucky since most apartments here have a ceiling height of 2,5m. Those 25 extra centimeters will be useful. - At last, I DO NOT INTEND to have a drum set being played in this room, and there will not be customers in. So no work after 8 pm. Here are the plans (see attached files): - 1. Side view and top view of the room now. - 2. How the room would be after acoustic isolation : I think about starting with the ceiling and the floor, then fixing the stud between them to prevent the original ceiling and floor from being ruined by screws. Moreover, I know that walls are big and sturdy enough to bear the wood beams. Not too sure about what the ceiling is able to. One last think, I want the isolation structure to be easily removable for the day we will sell the apartment. To start on, I would like to have your point of view about my way of doing things. Am I on the good way or totally wrong ? Thanks in advance for your informations :) Jerome PS : I hope everybody feels comfortable with metric system.

I would suggest that you should not try to support the inner-leaf walls on that semi-floated floor! Build them on the existing floor, which hopefully is NOT the way you showed it, as there is no support underneath the perimeter. You can't build those walls on top of an unsupported cantilevered piece of flooring: there has to be a structural member underneath that is able to safely support all that mass. Also, I wouldn't use plasterboard on the floor: Use plywood or OSB. Your ceiling is also an issue; you are showing a 4-leaf ceiling, with thin drywall and thin air spaces: that is going to give you very poor isolation in the low end. I'd skip the layer of drywall top of the new inner leaf ceiling, and use tow layers of 16mm drywall underneath. Or you could put them both on top, if you want to build it inside-out. Your diagram also shows that your inner-leaf is coupled to your outer leaf all over the place! The ceiling touches the existing walls, and the walls inner-leaf wall studs in turn are directly touching the existing outer leaf surface. You need to fix that, for sure. - Stuart -

Thanks for this answer. Floor : About the existing flooring, my diagram is very approximate as I cannot remove the parquet strips to see what is underneath. But I'm quite sure there is a support close to the perimeter. I update the diagram is this away and I will check that to make sure of it. I've chosen plasterboard on the ceiling because it is said in P. Newell's book that it's heavier than plywood. Moreover, it's much less expensive. Is it really better to use plywood or OSB than plasterboard ? Ceiling : I'm not sure my diagram is clear, but what I meant to do is to fix one leaf of drywall upon the beams and one leaf of drywall underneath the beam. As there is a window topping at about 30 cm under the existing ceiling, I need the new ceiling to fall 30 cm max under the existing ceiling. As the beams are approximately 15 cm high, there is 15 cm or air between the drywall leafs., and 10-15 cm between the top of the inner ceiling and the existing ceiling. I choose to fix the ceiling beams on the outer walls because I know these walls can bear it. I'm not sure of the composition of the outer ceiling, and I don't feel comfortable with fixing anything in it. Walls : The metal studs being screwed in the inner ceiling on top and in the new floor in the bottom, there is not much contact with the outer wall. The only contact would be the rockwool sandwiched between outer wall and new wall, but I thought rockwool was resilient material, isn't it ? Or does it depends on the density of the wool ? Anyway, I'm gonna make a new diagram following your information. Let's see if this is better :) PS : I'm not sure I can find 16mm drywall in France (we usually find 13mm). But I will check it out.

Here is my new proposition. Stuart, does it look better ? With some comments : - As far as possible, I wish I really could keep the existing oak floor intact by not screwing anything in it. That's why I persist in fixing things in the new floor (unless I am definitively convinced it is not possible or dangerous). - Same thing for the existing ceiling. I'm really not sure about its structure and it looks weak to me, unlike walls. - I was going for 2-layer plasterboard for the new floor because I would add a timber floor as finishing, and I thought it's good to mix material. - At least, I read in Philip Newell's book that the floating floor can support light walls if the density of the floating material is high enough.

"- The building is old (1895) and not very well isolated," If you mean insulated then can we assume a wooden structure and if it is wooden you might want to move downstairs or you could wind up there by gravity. If you really mean isolated, same thing applies since concrete would give more isolation even with flanking. "One last think, I want the isolation structure to be easily removable for the day we will sell the apartment." No comment.

If you mean insulated then can we assume a wooden structure and if it is wooden you might want to move downstairs or you could wind up there by gravity. If you really mean isolated, same thing applies since concrete would give more isolation even with flanking.

I'm not sure to understand the difference between 'isolated' and 'insulated' but what I meant is : Unlike recent buildings in which drywalls and fiberglass are often used, in my building there is only concrete or stone or brick walls with a plaster finishing. No insulation is used. As for the ceiling/floor, I hear my neighbour walking above, and I guess my neighbour underneath hears me too (which does not happen in new buildings).

"One last think, I want the isolation structure to be easily removable for the day we will sell the apartment." No comment.

My mystake... I mean I don't want to ruin the ceiling and especially the oak floor by fixing structure on them. I'd like to keep the floor intact once I will have removed the isolation structure :) Well, I know that what I'm asking is difficult, maybe impossible ? But I think this is an interesting challenge. And the real question is ; Is this really impossible or is there any solution ? :D

i strongly recommend Rod Gervais' new Home Recording Studio Build It Like The Pros 2nd edition book. it has a very excellent section on floating the walls and floor separately which would seem to be idea in your case where you want to minimize any potential damage to the floors or walls. basically you float the isolation walls on neoprene isolation mounts and your isolation ceiling sits on the isolation walls. then within the isolation wall space, you place rigid insulation on the floor (would put down some plastic or cloth first) and then layers of plywood and a finished floor (like engineered wood products).

Thanks Glenn for this information. The book will be out on 30th October here in France. I pre-ordered it. About making the ceiling sit on the isolation wall, hum... it looks complicated to me: if ceiling sits on the walls, it means walls have to be self-bearing, which is much more difficult to realize than plasterboard screwed on metal studs. It's also more expensive since I will need to replace metal studs (3 euro/piece) by wood studs (20 euros/piece). But I will consider that solution and see how much i will cost me. Meanwhile, here is the top view (approximation) of the inner shell (metal structure could be replaced by timber structure if necessary). I need your opinion about the window problem. I'm not sure it is good idea to "close" the inner wall on the outer wall on the perimeter of the windows. In he opening to the hallway there would be a double door (one at the existing wall, one at the inner wall, which is not yet represented on the diagram). Jay

About making the ceiling sit on the isolation wall, hum... it looks complicated to me: if ceiling sits on the walls, it means walls have to be self-bearing, which is much more difficult to realize than plasterboard screwed on metal studs.

Not harder to do at all! Unless you have some kind of building code requirements that does not allow you to build load-bearing walls with steel studs. It's exactly the same, in fact. Put up the studs and screw the drywall to it. Maybe you need cross-bracing, or sheer bracing, or some such, but that shouldn't be a big deal. One easy solution might be to substitute OSB or plywood for you first layer of drywall: that will give you an excellent sheer wall.

since I will need to replace metal studs (3 euro/piece) by wood studs (20 euros/piece).

Why? Is it that code in France does not allow steel framing for structural walls, or is it that you just can't get heavy enough gauge steel studs?

I need your opinion about the window problem. I'm not sure it is good idea to "close" the inner wall on the outer wall on the perimeter of the windows.

Exactly: it's not a good idea to do that. That creates a "flanking path" between the inner-leaf and outer-leaf. What you have to do there is to frame another window in the inner leaf, and put glass in it. The inner leaf has to be unbroken and sealed, jut like the outer leaf.

In he opening to the hallway there would be a double door (one at the existing wall, one at the inner wall, which is not yet represented on the diagram).

That's the idea: two doors, one on each leaf. Use the same concept for that window. - Stuart -

Humm.. first of all, I'm not sure we are talking about the same thing. Metal studs I'm talking about are aluminium light studs (1.4 Kg) and you can almost fold it with your arms or ruin it with a kick in it. You can see an example here : http://www.youtube.com/watch?v=stI91IL3Teo So I don't think it can be used to build load-bearing walls. It's usually used for light separation. Second, if the new ceiling sits on the inner walls, I'm quite sure that the exiting timber floor cannot support the load as it will have to bear the four inner walls and the new ceiling. In my method (with which we cannot reach such a degree of isolation, I'm aware of that), ceiling is supported by the massive outer walls (so no problem) and only the isolation walls are supported by the floor. Moreover I have the feeling that the new floor distributes better the load on the whole surface of the existing floor. At last, don't forget that I'm trying to realize a very LOW-BUDGET studio, which I may have forgotten to mention in my firt post. At the begining I just wanted to treat the room to get a better sound. Then I told myself "why do not improuve isolation so that I can be more comfortable in listening the productions?". So my question is : Is my method just throwing money down the drain, as flanking effect and acoustic bridges would ruin all my efforts? Or despite the faults, it will still have some effects and help me improuve isolation ? Thanks for your help :)

consider isolating the ceiling joists from the support wall using neoprene or Sorbothane under the end of each joist. you'll want to calculate the estimated weight of the ceiling structure and use that to calculate the thickness and hardness of the rubber so that is properly compresses and still retains enough spring and is structurally correct. you could isolate the new inner walls on something similar or something like ND isolators from Mason Industries. lastly you could "float" a floor of 2" (50mm) of 48kg/m3 rigid insulation and 2x 1/2" (12-13mm) plywood (overlapping seams) and then a layer of engineered wood to finish. all of the walls, ceiling, and floor are separated and you use backing rod and caulk through overlaps to seal. if you have Rod's latest book (2nd edition) he explains the wall and floor bits in great detail.

Thanks Glenn for that advice. I will work on a new diagram including those neoprene layers. What about the double window ? Is there not a way to avoid it ? :?

you could possibly remove the existing window and replace it with a single leaf window of heavier mass and then build another window inside with heavy mass as well. or if you cannot remove the existing window, consider blocking a portion of it and using a smaller interior window with mass so you still get some light and some of the exterior window is blocked in terms of sound (less ideal but sometimes you have to live with what you have).

I really don't like the idea of not having an access to the window :( Other possible options : - A slide glass door? Like the one you usually put between you living-room and you garden when you have a villa on the coast :) - Glass blocks in front of the windows to keep day light, no more access to the window :( - Is my method of joining the inner and the outer walls going to ruin all my isolation work ??

a slider works for me if it works for you 8) just consider the trade-offs in terms of isolation versus functionality and if that meets your needs then you are set.

I found this material under the trademark of Monarflex Verticalm. It is sold for "paste it on your wall and it will decrease sound by 2" :) No comment... Though, I wonder if this can be used as resilient material to replace neoprene pad under ceiling joist ? According to the technical sheet, it is an agglomerated foam of polyurethane and elastomer bitumen. One roll is 7,6m long and 0,5m wide, for a thickness of 5mm. One roll (3,8m2) weigh 15,82Kg. So if I didn't make any mystake, it's a 4,2Kg/m2 foam with a density of 832 Kg/m3. Would this foam work as a spring ?

not sure as the compression specs are not available. maybe contact the manufacturer to see if they have those. you'd want this to be the equiv of 45-50 hardness for neoprene.

Hum.. They couldn't even tell me the density of the material. I had to compute it by myself. As this product is not intended to be used as spring, I don't think they have compression rate available. So I'm looking for other products, and I may have found something interesting. When you talk about 45-50 hardness, do you mean compression ? And is the unity DaN (Deca Newton, I guess ?). I ask you because I find a website that sells many kind of anti-vibration pad (example in picture attached), and there is "compression" mentioned in spec, given as DaN. Other examples here : http://www.solutions-elastomeres.com/-S ... c,97-.html

more like this http://www.rubbersheetroll.com/neoprene ... _rolls.htm listed here as 50-60 durameter

My mystake... I found the hardness and the load in the spec. All I have left to do is to calculate the load :) Is 1 daN equivalent to 1 Kg ?

Hi all, Sorry for being away for months after starting a topic but wehad to deal with serious health problems. Now everything is fine and I'm ready to keep on working on my little studio :D I have one question about the floor. You advised me to use 2 layers of chipboard instead of 2 layers of drywall. Why not replace one layer of chipboard by a layer of drywall, like this (from top to bottom): - final layer (carpet, seagrass or sisal matting) - 19mm chipboard - 13mm drywall - 20mm of high density (140 Kg/m3) rock wool Drywall is cheaper than chipboard, and I think it is a little bit heavier (for a same thickness).

the drywall will crack...

Ok then. I will go for chipboard only. Is this ok (see attached picture) ? The two layers should absolutely be glued or they can be screwed ? Thank you

screw and or glue and screw to make sure it acts as a single mass