Single Car Garage Extension Belfast Northern Ireland

Hi Folks, Im Phil and Ive been lurking on the forum for about 2 years 25 days and 15 minutes.... I have a studio problem! Below is my garden with detached garage, the surrounding area is where i plan to extend the garage for my control room. My neighbours house is about 3 meters from my boundary. I Live beside a pretty noisy bus stop (90-95 spl when there's a bus) and fairly close to a 6 lane motorway. the lowest spl i could register outside was around 75 during the day... ive yet to measure at night. I have a budget of £18-20k for construction and materials. I am a DIY nightmare and plan to very little of the building. I have attached some design ideas below. I have a few questions (bottom of post) This is my initial design idea... its all pretty rough and is just to get a starting point for layout etc. Ive used the soffits and slot resonator designs from Johns sketchup plans... incredibly helpful. I have a set of mackie Hr824s so will be using the vented design (not shown) Im planing to build a custom console which is still very rough just really a layout of the gear. I mostly work on Electronic Dance Music so the control room is the most important part. I would like to have the option to record live instruments including drums but its not my top priority for the initial phase. My biggest worry is how to translate all the info on here to a builder to make sure things are getting done correctly... i am archiving as much info as possible e.g. wall construction methods and dos and donts from the FAQ section. My Questions. 1. What do i need to take in to consideration when getting the concrete laid with regards to coupling with the existing garage and burying pipes for cables etc. 2. I have a massive gap in the HVAC design (there isnt one) Ive searched the forums and a lot of the info applies to US systems or the products are no longer available... any one found a system in UK or Europe or could point me in the right direction or help guide me with what i need to be thinking about. 3. The walls in my design are breeze block for the main structure and stud wall with double layer plasterboard for the internal walls.. does this seem like the right idea? 4. what should i be looking for with the roof structure... the garage has a concrete flat roof... should i do something similar would a pitched roof be better. I think thats my main questions for now im sure i will have a ton more when i get going... I genuinely appreciate any help. This forum is such a fantastic community i hope to contribute as much as possible. Thanks Phil.

Looks pretty good overall...but in your control room you want the back to open up, get wider, not smaller...give the low frequency some expansion room.

So if I flipped the room 180 so the smaller end was where the console is would that work?

or just leave the walls straight and use the treatments in the front and back of the room to provide the angles and some absorption opposite the door.

I think Glenns' suggestion is the better of the two options...

Yeah i was wondering about oposite the door... from what i gather symmetry is a good thing but in this instance is more absorption better. Ive also often wondered would the likes of the absorbers and resonators be enough to dispel standing waves? so as you say i could just have the walls straight which would be much easier to work with. would the same apply to the small live room?

the absorption will handle the flutter echoes between facing surfaces. standing waves happen regardless. modal resonances will require treatment to bring it all into balance. having hard absorption like slats or perforated metal will help shift modes and introduce some diffusion as well.

Heres a revised layout. should the absorption opposite the door be slotted or not?

keep the soft absorption opposite the door. looks much better.

Thanks Glenn!! Really helpful advice... the room looks much better. Im now trying to fine tune the design a bit. How much of a gap should there be between the exterior walls and the interior studs.... is like 50mm enough? I was looking at Bob Golds Room Mode Calculator and there is a ratio that i could get close to 1 - 1.26 - 1.59 I have used a pitched internal celling structure which will mess the ratio up as the calculator accounts for a flat surface. Is there any way to take this in to consideration? or if my walls are at a decent ratio will that be enough... especially with the added absorption etc.? should i just use a flat celling?

Amazingly enough with all this discussion, I see no measurements for this/these rooms anywhere? Your existing height, whatever that may be, will dictate if installing a vaulted type ceiling is in the design or not. If height distance is already low, then you want to get a flat ceiling to maximize the volume for your room(s) Ratios are not scalable, per se, so if you don't have 10 feet high walls to start with, it isn't something to get worked up over. Still, keeping a good rectangular room , should you go that way, is always prescribed. People tend to want to make angled walls/treatments at this forum, since that is the form and practice that Mr. Sayers designs with. As to the distance, anything that immediately decouples the two assemblies is required, so the distance isn't such a factor in that respect. But if you have the room/foot print to add more space between walls, then more is always better, if you can maintain that separation across the entire build.

Agreed go with the flat ceiling and add angles via clouds and /or false ceiling rather than make the isolation layer concave like shown. If you do decide to make the ceiling angled, use a single angle from the front (lowest) to the back (highest). Use 6 degrees minimum angle.