Comments please on purpose built construction. sketch up inc

Hi all , Please help as want to order materials and get going but paranoid im going to buy something and regret it 'oh you should have used this its brilliant!' is something I'd like to avoid! Please see my plan for my purpose built studio ( music room ) Concrete base, height 2.5 mtr ... I want a band to play in there with minimal disturbance to neighbours . I would like to be able to play my drums along with a band (sax,guitar, bass guitar) I know you guys like a figure so i would say 100 db reduction.I know thats hopeful. I could build a bass trap thing to go over window when full band in there/getting loud my questions are ; 1. Is there an obvious improvement I could do without losing to much space? Ie bigger air gap and how much it would improve things per loss of space against say an extra plasterboard green glued. 2.How many sheets of board to use ive speced two (with green glue) 3. any spec on building a door ? Thank you .. 4. Also type of rockwool insulation to use ?

Concrete base, height 2.5 mtr ...

Not sure I understand: Your concrete slab is 2.5 m thick? :shock: :)

I know you guys like a figure so i would say 100 db reduction.I know thats hopeful.

Ummm... just a little more than "hopeful" I'd say. The very best isolated studio on the planet, called Galaxy Studios, in Belgium, is isolated to 100 dB. It took them years, and cost them many millions of dollars to do it. The basically built each room as a massive reinforced concrete bunker floated on major multi-layer spring isolation mounts, like this: (Photo credit: I think this is from Eric Desart: not 100% sure) According to an article I read, each control room weighs 252 tons and is supported by 78 of those springs, and it isolates down to 6 Hz.... So 100 dB is just a little on the ambitious side! :) A more reasonable figure would be around 50 to 60 dB of isolation. That's a bout as good as you can expect from normal construction. You might be able to get to 70, but that's stretching it.

I could build a bass trap thing to go over window when full band in there/getting loud my questions are ;

Bass traps are for room treatment, not isolation. A bass trap won't isolate at all, since it is basically just a thick piece of absorption, so that won't make any real difference to keeping sound inside the room. Isolation and treatment are two very different aspects of acoustics. Isolation keeps the sound in, which makes the room sound bad, and treatment makes it sound good again.

1. Is there an obvious improvement I could do without losing to much space? Ie bigger air gap and how much it would improve things per loss of space against say an extra plasterboard green glued.

A bigger air gap will always help, since it lowers the MSM resonant frequency of the wall, and an extra layer of drywall (plasterboard) will also help, since it increases the mass of the wall, which also lowers the MSM resonant frequency. Green Glue helps too, since it adds constrained layer damping to the drywall sandwich, which improves low frequency isolation. So all of those are good options. Your window glass is a bit on the thin side, if you want lots of isolation. You should probably have 16mm laminated glass for the inner leaf and 20mm or better for the outer leaf (total thickness of pane). The idea is to keep the surface density of each wall constant, so that there are no changes in mass.

2.How many sheets of board to use ive speced two (with green glue)

For extreme isolation, I'd go with a first layer of 19mm plywood or OSB, then two layers of 16mm drywall, all with GG in between. staggered joints, mud and tape, caulk, backer rod, etc. Really high levels of isolation require major attention to detail.

3. any spec on building a door ?

For that level of isolation, I would go with a pair of Rod's "superdoors", back to back, each with three full seals.

4. Also type of rockwool insulation to use ?

For mineral wool isolation in general Not just the Rockwool brand), you should be using stuff with a density of around 50 kg/m3. If you use fiberglass, then the density should be around 30 kg/m3. But one thing I don't see on your plans, is your HVAC system. High levels of isolation make that a bit more complicated, so that will need very careful design. One more thing: there's a green line on your diagram, to the top and right of the actual studio: what is that? It looks like a wall? If so, then you have a problem: that's a third leaf, and it will reduce the total amount of isolation you get, due the resonant characteristics of 3-leaf systems. - Stuart -

Hi thanks again, Ill adjust the window spec... Regards the garden walls I can not remove them or use them as part of my construction (party wall issues,) Ill go with your spec on the inner leaf wall assuming 19mm ply - Doors - ill do a search on your suggested. Height of building is going to be 2.5 mtr high. The concrete floor is 250mm thick, with the outside walls concrete block or engineering bricks. I am thinking to go for high density engineering bricks but labour costs will be higher as they are half the size of the concrete blocks Staffordshire blue brick Net Dry Density: 2200 Kg/m³(Typically) i think i can find one that is 2400 as well. though cant find link at mo. Concrete Dense aggregate blocks have a density in the range 1800 – 2100 kg/m3 Would a render sand cement on the internal side of the concrete bricks be worth the effort? (say 15mm thick ) ?? Thanks

Would a render sand cement on the internal side of the concrete bricks be worth the effort? (say 15mm thick ) ??

It would help in two ways: 1) more mass, and 2) sealing the surface of the porous concrete. - Stuart -