Garden studio plan in London, UK

Hi everyone, I'm from UK London (Originally from Asia so apologies for my English) planning to build a recording studio in my garden space. Hopefully I'm following forum rules and providing enough information to ask for help. It is completely ’new build’ which needs foundation work to begin with. Location is typical UK terraced house environment and the nearest houses will be at least 10 m away from where the studio is to be build. There are neighbour’s garden sheds on either side of the studio, as well as another neighbour’s garden shed and brick-built garage behind the studio. However, it's still in residential area so I must make sure the level of the soundproof is high-standard.Hopefully the building specs below will achieve good level of sound proof. Please take a look at 2 pictures. External building: Dimension - 7m(L) x 5m (W) x 4m(H) Foundation - Concrete slab on grade. 15cm thickness of the floor External wall - 440mm x 215mm x 215mm Solid concrete block Roof - Concrete Internal building: Control room and recording room are same size 4.16(L) x 2.9m(W) x 3m or 3.5m(H) and walls are parallel with each other... I can't think better layout to squeeze out the max spaces for each room at this stage. 2x4 (50mm x 100mm) stud wall with double layered 15mm dense plaster board sandwiched 2m dead sheet. 1, What is the most appropriate thickness of the concrete block that will be solid enough to soundproof the drum kit, 4x12 guitar cab and bass cabs 3 piece ensemble? 2, What is the most appropriate ceiling height and slant angles? 3, Sound proof material manufacturer told me 25mm air gap is enough between concrete wall and stud wall... Does this really work?? 4, Does the side of the stud wall facing the concrete wall need plaster board? What about room partition stud walls? 5, I'm thinking of having a sliding glass window to access between the two rooms rather than a door. Where can I find those in UK? 6, Do I need dead sheet type of material between stud frame and concrete floor? Do I also need the same for between ceiling beam and top of the stud wall frame? 7, Where would be the best place to install AC air ventilation? And what would be the best product in UK? (I am thinking of using Daikin split air conditioning system for each room) Sorry this is a rather long entry, but but it would be great if you guys could give me advices on design and specs.

Are you going to be using a beam and block construction for the roof? (as per your drawing)

Are you going to be using a beam and block construction for the roof? (as per your drawing)

Andy Brook wrote:

Are you going to be using a beam and block construction for the roof? (as per your drawing)

Yes, and will be covered by mixed concrete then water proof finish may have SIP board flat roof with gutter. Thanks Andy.

Have you already found a supplier for the beams? I can recommend Millbank - they were very helpful!

Andy Brook wrote:

Have you already found a supplier for the beams? I can recommend Millbank - they were very helpful!

Thanks Andy!! Is this the one?? http://www.milbank.co.uk/beam-and-block.php

Hi, just a wonder: did you already get planning permission for such a tall studio? In UK the limit is 2.5mt, specially since you are less then 2mt from the boundaries. It would be interesting to know (I am about to do a similar construction myself!welcome on board!). Otherwise the other option is to dig down, which is a bit more complicated. AC is a concern to me too. No answer yet but if I know something I'll post it here.