Room shape for new studio build

Hi all, I'm new to the forum but i've done the required reading now (I think!) and I'm after a bit of help on room shape. I'll keep this post fairly simple as it's just the basic shape i need some help on and the parameters are not that flexible. I'm building a small project studio in London, England with a target budget of around £10k (12 tops). I've done a preliminary design with a roof and internal ceiling sloping at 8 degrees to help with reflections (see idea 1 below). The walls and roof will be a double leaf design around 30cm thick with a 10cm deep floor. This means that the internal height of the room at the low end is only 2 metres and I am concerned this is rather low. In an attempt to rectify this i have come up with another shape for the roof with a flat section at the high end (see idea 2 image). This will allow me to raise the level of the low end without increasing the overall height of the building. What I am wondering is how much of the roof needs to be angled to gain any benefit acoustically. Can I get away with angling only half the ceiling as in the second pic below? Many thanks, Dave

I would take a look at this post in which Andre and others helped me to understand the ins and outs of angled ceilings and splayed walls. Good stuff for anyone wondering about the subject.

Hi Brian and thanks very much for that. I'm not sure I'm that much wiser having read that thread as it's clearly a contentious subject! In my case I think I more or less have to do an angled roof. It's what I've drawn on the initial planning application and the angle makes the building a little less imposing for the neighbours. Since I can't reach an ideal height inside the room i'd also like to maximise the volume of the space. Any other thoughts on the subject are most welcome! Thanks again, Dave

Hi all, My design is progressing a fair bit now and a few questions have come up that I'm finding hard to answer. Below is a pic of the construction scheme so far. (building elevations are at the start of this thread) I've read the stickies and several threads on floating floors but I think my brain is approaching critical mass :? I realise I don't actually have to float the floor as the build is on a large concrete block and the floor will be inside the double wall, but there are two reasons i'd like an airgap there. Firstly i don't want to be directly on the cold concrete as I'm bound to end up sleeping in there at some stage... Secondly, it would be great to have somewhere to run the mains electricity cables, maybe even to sockets in the floor. This would allow for a minimum of holes in the walls and help me maintain my precious isolation. Bearing this in mind: Do I actually need to mount the floor joists on neoprene or similar springy feet? What would be the best combination of floor layers to avoid nasty resonance? (would Green Glue help here?) On a slightly different point: It was suggested by the guys at http://www.whitemark.com that i should use plywood as my first drywall layer attached to the studs. This makes it easy to screw on additional layers with plenty of space for screws. Does anyone see a problem with this? Finally - what should I use between the drywall and the concrete plinth? I have currently included sheetblok in the design but as it's by Auralex I realise I'm in dangerous territory... Thanks in advance for any answers! :thu:

Where to start with what you have shown... If you believe a floating floor is necessary, which I do not, then use 50" of 48 kg/m^3 density glass based mineral wool with no stringers or neoprene. The closest testing of a similar wall in IR 586 (see figure 4, pdf page 9) show a TL greater than 28 dB from 63 Hz up and TL over 60 dB from 500 Hz up. With no coupling between the concrete and studs except for the floor and double plasterboard, I would estimate the TL would be over 66 dB from 400 Hz up. Reduce the space to just enough to assure no mechanical touching. Use two layers on the inside, not three. Green Glue is expensive (~$35 per sheet of drywall sandwich), you don't need it. The outside skin acts a third leaf reducing TL at low frequencies. USe stucco or material adhered directly to the concrete block. Remember you are saving a lot of money by not using Green Glue. The weak point is the roof. Consider a concrete roof to somewhat match the concrete wall isolation. Obviously it will not be as thick, but it is the cheapest way get mass. These changes may seem daunting, but you will get better isolation, more interior space, and spend less money. I think that is enough surprises for starters. Andre

Hi Andre, Thanks very much for taking the time to have a look at this - it's seriously appreciated. Sorry to assail you with more questions but this stuff is keeping me awake at nights!

If you believe a floating floor is necessary, which I do not, then use 50" of 48 kg/m^3 density glass based mineral wool with no stringers or neoprene.

I don't think it's necessary either but do you think it would be ok to have a slightly raised floor (insulated as in the diagram) for running cables?

Reduce the space to just enough to assure no mechanical touching.

That seems like a good idea to me but it has highlighted another possible issue - I should have mentioned before that I'll need some space between the walls as i'm hoping to run a small HVAC system. I ought to check how big the ducting will need to be and where it's supposed to go...

With no coupling between the concrete and studs except for the floor and double plasterboard, I would estimate the TL would be over 66 dB from 400 Hz up.

Does that mean i've actually designed a good wall??! :D

Use two layers on the inside, not three.

Did you mean two plasterboard layers or 1 ply and 1 plasterboard?

The outside skin acts a third leaf reducing TL at low frequencies.

Yes, sorry that was slack of me not to work that out. :oops:

The weak point is the roof. Consider a concrete roof to somewhat match the concrete wall isolation. Obviously it will not be as thick, but it is the cheapest way get mass.

Ok now you're scaring me! I'm not sure if you've seen the choice of angled roofs I'm thinking of (first post in this thread) but I can't imagine either would be easy to do in concrete. How would that work in practice? Many thanks again for the invaluable advice. Dave

Not sure if this will help matters but i've bought a sound level meter and done a few readings in my current room to try and assess how much noise I need to contain in the new studio. The current room is roughly (l)3m (w)4m (h)2.7m with no acoustic treatment and the speakers close to the wall. :oops: I placed the level meter at listening height, 1m from the speakers and played full range music (aggressive breakbeat with distorted guitars and vocals) at a loud working level. I rarely go above this level for day to day work - my ears object quite quickly if it's too loud. The readings for this were 86-87db A weighted and 96-99db C weighted with the meter speed set to 'slow'. I also have an upright piano which I gave a good thrashing but that didn't seem to be anything like as loud as the speakers. The neighbours are pretty close by and live in flimsy houseboats so I need to keep the leakage to a minimum but I don't want to over-engineer the studio and use up too much money or space. All thoughts welcome!

ragman wrote:

Firstly i don't want to be directly on the cold concrete as I'm bound to end up sleeping in there at some stage...

lol

ragman wrote:

Do I actually need to mount the floor joists on neoprene or similar springy feet? What would be the best combination of floor layers to avoid nasty resonance? (would Green Glue help here?)

id say no, but im no acoustic expert...

ragman wrote:

On a slightly different point: It was suggested by the guys at http://www.whitemark.com that i should use plywood as my first drywall layer attached to the studs. This makes it easy to screw on additional layers with plenty of space for screws. Does anyone see a problem with this?

i like this idea!

ragman wrote:

Finally - what should I use between the drywall and the concrete plinth? I have currently included sheetblok in the design but as it's by Auralex I realise I'm in dangerous territory...

take your timber 'floating' floor right under your internal partition. screw your wallplate to the floor battens.

Hi elektrasoul and thanks for your thoughts :D I'm glad you like the plywood on studs idea. It made sense to me from a convenience point of view. Even more so when I saw that White Mark's clients included Realworld and various Hit Factories. Very nice people too. I gave them a quick call and got some really decent advice without having to pay the usual £600 per day :shock: When you suggested

take your timber 'floating' floor right under your internal partition. screw your wallplate to the floor battens.

Just wondering what the advantages might be. Wouldn't that just create an escape path for sound through the floor? My thinking is that I would then need to make the floor the same thickness as the inner wall which I'd like to avoid if possible. I'm still looking into the concrete roof option though I think it may be too tricky for this build - trying to get advice from someone who used to build nuclear misssile bunkers :P If you're out there Andre, please throw any more surprises you have at me now! Cheers guys, Dave

Just thought I'd post an update: After much thought about concrete roofs and a good deal of discussion with the guys at studiopeople.com I've changed my plans to a standard 35 degree pitched roof. The flat one was going to make the space too tight and they also usefully pointed out that it would have been as ugly as hell! This means updating or re-submitting my planning application but it will be worth it in the long run. I've also had to double the budget to around £20K as reality set in... I'm aiming to employ studiopeople for the internal part of the build (plus HVAC) so hopefully it will end up looking the part. I'll start a new thread with lots of pics when i get into the construction phase. I really hope this is 90% design and 10% construction or I'll be dead before it's finished. :roll: Thanks for the help so far. Dave