John Sayers' Recording Studio Design Forum Archive

Hey there!



First off, please excuse the sometimes poor choice of words, my native language is German.



Where am I located?

I have the attic of a farmhouse in the countryside of Dorsten, Germany. The room is about 100 square meters, which is about 1076,39 square feet.

The ceiling isn't straight, it's slanted towards the top (see pictures below) and is supported by huge wooden beams and brick walls.



What I want to do:

I'm planning to build a studio with two freestanding rooms within a room. The walls are supposed to be made out of 4x plasterboard and metal support beams with stone wool (absorption material) in between. This room should be completely acoustically isolated from the building, so for the floor I want to make a construction out of wooden beams, which are acoustically isolated from the ground. You can see a rough blueprint in the pictures below.



How loud am I going to be?

Very loud. I want bands (including my own) to be able to play live and loud in there. So I'm guessing it's gonna get around 120dB.



Now my question is: Would it be a good idea to build a floating floor? If not, how can I find out the resonance frequency of the ground beneath me and the poles around me? If I were to build a floating floor, whats the best solution for isolating the floor construction from the ground? I've mostly seen people using those "U-boat" rubber elements between the wood and the ground, the problem is just that they're pretty expensive and I'd be spending about 800€ just on those, I'd need to put more on the outskirts of the platform to acommodate the weight of the walls on it. I've also heard of people using springs but I wonder how that would work, since I figure the structure-borne noise would still get to the ground through the springs, wouldn't it? Is there anything else you recommend or do you have any general tips in this department?



Thanks for your help, you might be seeing me post a couple of other topics aswell because I've heard a lot about this forum and hope some of you may be able to help a construction novice like me out.



Cheers,

Mika

AlvaMusicProductions wrote:Hey there!



First off, please excuse the sometimes poor choice of words, my native language is German.



Where am I located?

I have the attic of a farmhouse in the countryside of Dorsten, Germany. The room is about 100 square meters, which is about 1076,39 square feet.

The ceiling isn't straight, it's slanted towards the top (see pictures below) and is supported by huge wooden beams and brick walls.



What I want to do:

I'm planning to build a studio with two freestanding rooms within a room. The walls are supposed to be made out of 4x plasterboard and metal support beams with stone wool (absorption material) in between. This room should be completely acoustically isolated from the building, so for the floor I want to make a construction out of wooden beams, which are acoustically isolated from the ground. You can see a rough blueprint in the pictures below.



How loud am I going to be?

Very loud. I want bands (including my own) to be able to play live and loud in there. So I'm guessing it's gonna get around 120dB.



Now my question is: Would it be a good idea to build a floating floor? If not, how can I find out the resonance frequency of the ground beneath me and the poles around me? If I were to build a floating floor, whats the best solution for isolating the floor construction from the ground? I've mostly seen people using those "U-boat" rubber elements between the wood and the ground, the problem is just that they're pretty expensive and I'd be spending about 800€ just on those, I'd need to put more on the outskirts of the platform to acommodate the weight of the walls on it. I've also heard of people using springs but I wonder how that would work, since I figure the structure-borne noise would still get to the ground through the springs, wouldn't it? Is there anything else you recommend or do you have any general tips in this department?



Thanks for your help, you might be seeing me post a couple of other topics aswell because I've heard a lot about this forum and hope some of you may be able to help a construction novice like me out.



Cheers,

Mika

Hi Mika,

Welcome to the forum.

That's a very cool building you have there! Regarding your floating floor question, please read this thread:

http://www.johnlsayers.com/phpBB2/viewt ... f=2&t=8173

I think you'll find that a floating floor is not necessary in your case since it looks like you have a concrete slab on grade (in the earth). Such a floor already has a very low resonance and is infinitely damped by the earth. Putting anything on top of this will likely make things a lot worse, including a floating timber floor (with our without "u boats") as you will not be able to beat the mass or resonance of the existing concrete slab on grade.

The flanking between the control room and tracking room is not likely to be a problem at all, since when recording we are usually monitoring the same sound in both rooms therefore extreme isolation between the two is not necessary. I would expect the flanking to limit the transmission loss between the two rooms through a shared concrete slab to be around 60db. If this is not enough then you can always cut the slab into two independent slabs, but honestly I do not think you'll find it necessary.

In order to do a fully floated floor properly and have it be useful, you would need to float another concrete slab on top of your existing one using a resilient "spring" such as those sold by Manson industries. Once the concrete slab is poured over the springs, the springs can be further adjusted to tune them to the target frequency, this is a way to achieve maximum isolation (over 70db) at frequencies down to 5hz. This is incredibly expensive and risky and usually unnecessary. It is used by professional studio builders in situations where the studio is next to a train station for example.

In any case, depending on exactly how you build the rest of your structure the floor is probably not going to be the weak spot.

Have you already planned your air con and ventilation system? How about your structural venting? These are all potential weak spots due to penetrations in the isolated assembly.

Please keep us updated on your progress.

Paul

Hi Paul,

Thank you for the reply and the great thread!

As for the slab, I think I forgot to mention it's not actually on grade, it's on the first floor (it's the "attic" if you will, of an old farmhouse) and right next to it lives my family, so I'd have to really isolate it, at least I think I do. What does that tell me about the resonance frequency situation, would a floating floor work better or make it worse if I'm on the first floor of the building?

I already have some ideas a ventilation system, maybe one or two of these (https://www.lueftungsmarkt.de/helios-zl ... wandeinbau) build into the walls of the room, connected to a large (16cm diameter) tube, which goes to the outside through the outer roof of the building. There is also a heating unit that can go in-between the tubes and the ventilator, so that the air gets heated up. Still, just an idea, if you have more advice on ventilation and air conditioning please let me know!

Cheers,
Mika

AlvaMusicProductions wrote:Hi Paul,

Thank you for the reply and the great thread!

As for the slab, I think I forgot to mention it's not actually on grade, it's on the first floor (it's the "attic" if you will, of an old farmhouse) and right next to it lives my family, so I'd have to really isolate it, at least I think I do. What does that tell me about the resonance frequency situation, would a floating floor work better or make it worse if I'm on the first floor of the building?

I already have some ideas a ventilation system, maybe one or two of these (https://www.lueftungsmarkt.de/helios-zl ... wandeinbau) build into the walls of the room, connected to a large (16cm diameter) tube, which goes to the outside through the outer roof of the building. There is also a heating unit that can go in-between the tubes and the ventilator, so that the air gets heated up. Still, just an idea, if you have more advice on ventilation and air conditioning please let me know!

Cheers,
Mika

My bad - you did mention it was an attic but I obviously forgot that part while I was replying. So how is the floor constructed currently?

This does complicate the build since you'll need to find out how much weight the existing floor can take, for dead and live loads. It is also very, very difficult to isolate a space with a room below it effectively, this is because your outer leaf (your existing building) is attached to the rest of the house. The walls connect to the rooms below, so even if you isolate the floor and build a new inner room, the outer room will still transmit vibration throughout the rest of the house. So the best you can do is a new, very dense inner room, but accepting that your outer leaf will be compromised. So yes, in your case a floating floor will be needed. How you build the floating floor depends on a few factors...

I think I would get a structural engineer involved and come up with a plan of how you can safely build a decoupled free standing room within your existing space - I do not know the regulations in your country for carrying out such a build.

I also think you need to accept that you will only be able to gain so much isolation - it will not be perfectly quiet in the rest of the house, especially low frequency energy.

A couple of things I would do/think about straight away:

- You need to make your existing space as airtight as possible. Seal every crack, hole, gap etc in the walls, floor and ceiling/roof. Use a non hardening caulk and if the gaps are big then use backer rod to fill the gap first, and then seal.

- You probably have a vented roof, which means there will be penetrations to let air in and out so that condensation doesn't form on the underside of the roof deck and on the timbers. You cannot block this ventilation up, but you also need an air tight building, so what to do? It depends on what type of ventilation you have (soffit vents, ridge vent, tile vents, felt lap vent etc) so let us know what you have there, but you'll probably have to put plywood/plasterboard on the bottom of your rafters, leaving an air gap (at least 50mm) so that air can freely come in and out and keep the roof deck ventilated. The new plywood/plasterboard will be a continuous layer that is sealed all the way around and meets the walls to form a complete airtight "bunker". Then you'll build a whole new inner room within that bunker.

- You mention that you have brick walls - that's good. But your ceiling will need to at least match the surface density of the brick in order for it not to become the weak point in your build. It's going to be very difficult to match the density of brick using plywood and plasterboard, so you'll have to increase the air gap at the ceiling to make up for the lesser mass. This means your internal height will be a lot lower than it currently is. Also, the current beams are going to get in the way and not enable you to maximise your height. I would speak to your structural engineer to see if they can be removed and another method to support the roof put in place.

- Once you have your sealed outer shell and your new sealed inner shell you'll have to penetrate it to put fresh air in and take stale air out. The ventilators that you linked to will not be good enough to maintain a high level of isolation because they are very lightweight and provide a direct connection between inner and outer leaves. They also look quite small which means they likely would not provide enough fresh air for more than 1 or 2 people. You'll need a complete HVAC design which maintains isolation but provides enough air for your needs. Then you'll also need at least cooling, so you'll an air conditioner, and they usually have an outside unit. This means you'll need space for that somewhere outside, and then you'll need to work out how to connect it to the attic space.

Those are my thoughts for now, hope it helps.

Paul