Soundman2020 wrote:Source of the post Hi there Sam, and Welcome to the Forum!
Thanks for the welcome! Hopefully I can add something, with my build, that will be valuable for future builders!
I’m looking to build a humble recording/mixing studio at the bottom of my garden.

I bet that's how you feel, after taking the decision! Congratulations!!!
Thank you!
My main current issue is deciding on the roof type
Considering that you are going with Permitted Development rules, and the related height restrictions, I would suggest going with a she roof that has minimum possible slope, to maximize interior ceiling height. Another option might be a shallow gabled roof. Either way, the point is to get your eve heights within the limits while still getting the best possible ceiling height.
'She' roof? sorry, what is that? I think I need a flat roof to maximise height. Permitted Development rules state: If The building is to be placed less than 2.0m from the boundary of the property (and mine is 1 meter away from the fences) with a maximum overall height of no more than 2.5m from existing ground level. so 2.5m is the MAXIMUM height I can go to. Although a loop hole is that the height of the 2.5 max is taken from the land adjacent to the house. As the garden slopes down considerably (0.3m to front of proposed studio in fact) I can build it 0.3m higher and still be within the Permitted PLanning rules. I have checked this extensively and with the local planning dept.
Preempting Stuart, obviously a mix room and a tracking room require two different environments.

I hear you! sometimes, you have to do what you have to do. So what is the PRIMARY purpose of the room? Is it mostly just a practice / rehearsal / tracing space that will also get used for occasional mixing? Or is it primarily a mix room for turning out paid work for clients, then occasional rehearsal / tracking. Whichever you define as the primary purpose should be the treatment goal to aim for. Then figure out how you can modify that treatment to make it adjustable, so you can also meet the secondary objective as much as possible.
Great question. I think mainly I will use the room to write/record all my own personal music and then also to mix/rough master. So both really. It will mainly be myself in the room and sometimes one other band mate that I write with. No paid clients though.
I did see Stuart had posted an informative piece about some hinged panels that swing out to help make the room feel more live when tracking but cannot find it now
You mean this one?
What is variable acoustics? How do I do that? Thanks! I will read again.
The structure Build will be pretty standard; 2 leaf timber structure 25mm apart
When you say "25mm", I assume you are referring to the gap between the framing for the outer leaf and the framing for the inner leaf? 25mm air gap would be too small, but 15mm framing gap is probably fine... assuming you are going with conventional construction. However, in your case you might want to consider doing "inside-out" construction, which seems to take up more room at first glance, but actually takes up less in the end, and can be very effective at maximizing use of space and also acoustic response. Especially if your primary goal is mixing.
Sorry, yes. 25mm between timber leafs. 25mm is too small but 15mm is OK? you got me there
I will research the 'inside out' method. Thanks
plasterboard and green glue/techsound (not as effective as GG but easier to apply)
Techsound is fine, as long as you understand that the two products are entirely different, and will not give you similar performance to GG... They work on different principles. In fact, GG isn't hard to apply: just a bit messy! Things can go up quite fast and simply, if you follow the instructions. And if you need good isolation for minimum loss of space, then GG would be the best option.
I'm not against GG it's just slower to apply.
I am building under ‘UK Permitted Planning’ rules
Do you mean "Permitted Development"? Or is there something else now, called "Permitted Planning"? Maybe I'm behind the times...
Permitted Development, yes. Sorry. As above.
I have a restriction of 2.5m high externally, however, as my garden slopes down I have calculated a 2.8m max external height
With Permitted Development, 2.5m is for the eaves, but you can go to 3m for the apex of the roof: Permitted-development-eaves-extract.jpg With careful design, you can get a finish ceiling height of over 2.6m at the highest point, if you are OK with a slanted inner ceiling. Even if you do a flat ceiling, you can still likely get better than 2.3 m: don't forget that the 2.5 m limit is at the eaves, which they define as the point where the outer surface of the wall meets the roof.
As above. 2.5m (2.8 in my case) is the total max height as I am within 2m of boundary: If The building is to be placed less than 2.0m from the boundary of the property (and mine is 1 meter away from the fences) with a maximum overall height of no more than 2.5m from existing ground level.
Closest neighbour's house: 50 meters in all directions!

Lucky you! That's great.
Yep!
Seems that to maximise height the Roof should be ‘cold’, however, after reading Rod’s book (nothing about cold/warm roofs and studio design in there that I could find) and lots of forum searches
I'm wondering if you are talking about "ventilated" and "un-ventilated" roofing? Ventilated means that there is an air path from outside, under the eaves, across the underside of the roof deck, and out through the apex (often a ridge vent). Un-ventilated means that there is no such path, and the roof is completely sealed off from the outside world, in which case you need to take other precautions to prevent condensation and moisture problems. Ventilated is simpler, but usually implies a 3-leaf roof. Un-ventilated is a bit harder to pull off, but can save you space...
Looking at flat roofs, I have consistently come across War roof vs Cold Roof:
https://www.spacetwo.co.uk/blog/2016/8/ ... cold-roofs Yes, I think you are right, it's ventilated vs not.
A ‘warm’ roof, in a room in room design seems to be a waste of space as the internal room is sealed from outer roof?
The inner-leaf room is ALWAYS sealed off from the outer-leaf roof, no matter which way you build the outer-leaf roof. One of he keys to isolation is that both leaves mys be completely sealed, hermetically, air-tight. Which is why a ventilated roof implies a three-leaf system; the middle leaf is what seals you off from the outside world. It is part of the outer leaf, but seals off the space with respect to the ventilated deck.
I think I understand. Given my height restrictions, please indicate what I should do here.
Windows/doors (UPVC with ‘acoustic glass’ on both leaves): I want a main triple-glazed front facing window with an adjacent door.

Triple glazing implies three-leaf! Which in turn implies increasing mass even more, and mostly on the middle pane of glass. That could be expensive, getting someone to custom-build windows and doors like that. It would be much better to go with just single glazing on each of the leaves, and use what you already suggested for that: laminated glass with acoustic PVB. That will maximize isolation while avoiding the issues associated with multiple leaves. If your building regulations require double.glazing in the outer leaf, then you can work around that. Hopefully that isn't the case with Permitted Development.
Thanks. Yes, that is what I meant. I will use single glazing windows/doors on both leaves with acoustic glass as you suggest. I don't have to adhere to Building Regs as I am 1m away from the boundary. I will of course build to Building Reg standard to ensure a solid build.
I know windows compromise isolation
Not necessarily! If done properly, there's no reason to lose isolation from having windows. It only becomes problematic when people want operable windows (ones that open), but for simple fixed-pane windows, its not a problem. You might find this useful:
site built windows for high isolation Great to hear. I will have an opening main window for days that I may work from home, i.e. no music.

Build start date: August/September
Wow! That's a really tight deadline! That only gives you about a month to get the complete design done! Whew! That's going to be HEAVY going! It normally takes me a couple of months to do a full ground-up design like this, so you will have your work cut out for you! That's going to be tough. You might want to re-think that.
I can push back the build month to October but I have nearly finished the Sketch Up drawing, so should be doable, I hope?
HVAC: Small AC all-in-one unit
I would not recommend that. It will be very noisy, and impracticable to use in a studio. You would have to put it off any time you needed to track instruments, or do critical listening for mixing. Thus, the temperature and humidity swings would be rather wild. Here's an article I wrote a while back about HVAC in studios:
Why your studio needs proper HVAC. I'm not sure if I have explained it properly but have a friend who has a unit with the main fan on the back of studio and Air con/heat inside. I have no problem turning it off when tracking/mixing.
I have estimated that I am looking to achieve a 40-50 db of reduction of sound.

A reasonable goal, and achievable.
Cool!
Like I said, I at least want to get the basic structure built this year, so will do it in stages:
It is fine to build in stages! Many people do that. But it is very important to have your entire design completed first. The reason being that you won't know here the outer leaf doors and windows will be until after you have completed the inner-leaf design, complete with all the treatment. That sounds strange, but is a very real issue. I could tell you several horror stories of people who built something first, then tried to build the studio inside it... and ended up having to move doors, windows, and electrical work so that they could have a usable studio. Simple example: you can't know where your side windows will go until you decide on which design concept you are going to use, and have done the layout for the optimal speaker and mix positions, and the necessary treatment locations... Ditto for the HVAC: You can't know where the inlets and outlets will be, or where the AHU will go, until you have most of the interior already figured out. Etc.
Thanks! I hear you! I want to get it right, that is why I am designing the location of the doors/windows for both leafs now. Obviously I need help with the roof design and working out the ventilation.
So I would urge you spend the first few months just designing, then build the basic structure once you have a complete design in place.
Good plan. Hopefully I can do it a bit quicker as this is not a commercial studio build, more of a glorified music shed in my garden.
- Stuart -