What can I tell my builder to get some isolation?

[ionionalanonalan]

I'm getting an extension on my house and at the same time getting a little studio built in the back yard. It's just going to be a 3x4 metre little room at the back of the block, weatherboard, insulation, plasterboard. I'm a freelance audio producer and this will be my primary place of business (ie every day in there making stuff with sound). However, it's an expensive renovation and I can't afford to spend more than i'm already spending, so i'm hoping there are some things I can get the builder to do as part of the job that won't freak him out into starting to add on a bunch more expenses.

I've read a lot online and watched a bunch of videos and I am getting that there is a LOT I could do to isolate the room, but it all sounds pretty expensive, so i'm hoping for some thoughts on what I can tell the builder to get a DECENT result (ie I realise it's not going to be perfect without some more money to spend).

Edit:
Use case - I am a composer / producer. I write and produce music for ads, bit of TV and hopefully soon more TV and film. Infrequently record a vocal part or voiceover, or maybe a guitar here and there. So mostly i'm producing / writing at the desk and in the box.
The room is going to be 3x4m, will border the neighbours yard on one side, a big brick warehouse on another side and my backyard on the other two sides. Screenshot of the plans attached.

[John Steel]

Hello & howdo' ionionalanonalan?
Is it possible to have a bit more information about what you want to achieve with your studio build please? Do you have drawn plans? Do you want to build a single room or more? Do you want to record, mix, rehearse or all of these things in there? How loud are you likely to be doing this and how loud is the environment surrounding your studio (in dB). Where is it located and last (but not least) what is your budget? The more detail you can provide, the easier it will be to help you. Best wishes, John.

[Paulus87]

I'm getting an extension on my house and at the same time getting a little studio built in the back yard. It's just going to be a 3x4 metre little room at the back of the block, weatherboard, insulation, plasterboard. I'm a freelance audio producer and this will be my primary place of business (ie every day in there making stuff with sound). However, it's an expensive renovation and I can't afford to spend more than i'm already spending, so i'm hoping there are some things I can get the builder to do as part of the job that won't freak him out into starting to add on a bunch more expenses.

I've read a lot online and watched a bunch of videos and I am getting that there is a LOT I could do to isolate the room, but it all sounds pretty expensive, so i'm hoping for some thoughts on what I can tell the builder to get a DECENT result (ie I realise it's not going to be perfect without some more money to spend).

Hi,

Do you actually need isolation? How loud is do you expect it to be inside your studio? How close are the neighbours? Any live instruments? Mixing?

Every project is different, with different requirements, and different levels of isolation, therefore it's impossible to advise without knowing more about your needs. Be as specific as you can and you'll receive specific answers.

Paul

[DanDan]

Many builders these days will use thermal insulation in wall voids, in order to achieve high thermal ratings. This can affect house prices here.
Aeroboard and Phenolic Insulations are three times better than fibre, but have no acoustic benefit at all.
Properly damping a void by filling it fully but not compressed, using light cheap fibre (acoustic blankets or rolls, for purpose) can add 9dB of isolation. Free lunch.

[ionionalanonalan]

Hello & howdo' ionionalanonalan?
Is it possible to have a bit more information about what you want to achieve with your studio build please? Do you have drawn plans? Do you want to build a single room or more? Do you want to record, mix, rehearse or all of these things in there? How loud are you likely to be doing this and how loud is the environment surrounding your studio (in dB). Where is it located and last (but not least) what is your budget? The more detail you can provide, the easier it will be to help you. Best wishes, John.

I've added more detail to my original post - thanks!

[ionionalanonalan]

Actually need isolation? How loud is do you expect it to be inside your studio? How close are the neighbours? Any live instruments? Mixing?

Every project is different, with different requirements, and different levels of isolation, therefore it's impossible to advise without knowing more about your needs. Be as specific as you can and you'll receive specific answers.

Paul

I've added more detail to my original post. Would also say at the moment the neighbours aren't too noisy (old women on either side) but given they're older neighbours the time will come when they sell up / are gone and I get a young family move in, which I am afraid of.

[Paulus87]

Actually need isolation? How loud is do you expect it to be inside your studio? How close are the neighbours? Any live instruments? Mixing?

Every project is different, with different requirements, and different levels of isolation, therefore it's impossible to advise without knowing more about your needs. Be as specific as you can and you'll receive specific answers.

Paul

I've added more detail to my original post. Would also say at the moment the neighbours aren't too noisy (old women on either side) but given they're older neighbours the time will come when they sell up / are gone and I get a young family move in, which I am afraid of.

Thanks for that!

So your main concern is actually the noise coming into your studio from the outside rather than the other way around?

I'm guessing that's because your studio itself will be very quiet; you won't be recording acoustic drums or loud bass/guitars? and you mix at a conservative volume?

You'll find that by keeping sound out you'll automatically keep sound in, so having said that, in your case it's difficult to judge since the building isn't built yet and so you cannot know how much isolation you're getting already.

You say you can't do much to change the construction materials or plans and your current assembly is: Weatherboard - insulation - plasterboard?

I'm assuming this is a timber frame build? What size are your studs/roof framing?

The weatherboard, is it a type of cement board? How thick is it? Is it large continuous sheets or small planks on top of each other?(like siding).

How about your roof? What is the internal height? Is it a cold, vented roof (If so, soffit vents? ridge vents?) or is it a non-vented warm roof?

How about your floor? Is it built on a concrete slab directly in the ground?

Any windows? How many doors? What type of glass/door?

Lastly, are you worried about your acoustics inside the studio at all or do you only use headphones?

Lots of question again I'm afraid!

Paul

[ionionalanonalan]

Actually need isolation? How loud is do you expect it to be inside your studio? How close are the neighbours? Any live instruments? Mixing?

Every project is different, with different requirements, and different levels of isolation, therefore it's impossible to advise without knowing more about your needs. Be as specific as you can and you'll receive specific answers.

Paul

I've added more detail to my original post. Would also say at the moment the neighbours aren't too noisy (old women on either side) but given they're older neighbours the time will come when they sell up / are gone and I get a young family move in, which I am afraid of.

Thanks for that! So:

- Correct - I mix at a reasonable volume in monitors (so I make some noise, but not crazy amounts and never drums), so I guess I am mostly worried about sound from the outside;
- It's a timber frame build on a concrete slab. I can't figure out the size of the studs etc from the architect/engineer's drawings - bit confusing;
- Weatherboard is wooden planks (so I guess kinda like siding);
- Internal ceiling height is 2400mm.
- Not sure of what kind of roof/venting - from the diagrams it looks like it's just a flat roof on a slight incline.
- One window and one door. I'm getting a solid core door and a fairly small window.

[Paulus87]

Thanks for that! So:

- Correct - I mix at a reasonable volume in monitors (so I make some noise, but not crazy amounts and never drums), so I guess I am mostly worried about sound from the outside;
- It's a timber frame build on a concrete slab. I can't figure out the size of the studs etc from the architect/engineer's drawings - bit confusing;
- Weatherboard is wooden planks (so I guess kinda like siding);
- Internal ceiling height is 2400mm.
- Not sure of what kind of roof/venting - from the diagrams it looks like it's just a flat roof on a slight incline.
- One window and one door. I'm getting a solid core door and a fairly small window.

Okay, so since you do not want to spend much more money you won't be able to have a double leaf assembly (a room within a room), however, your isolation needs are much smaller than normal so I would do a non-decoupled double leaf assembly, which means you still have two layers of mass separated by an air gap but the mass layers share the same framing. It should be sufficient for your needs.

From the limited info we have your biggest issues with keeping external noise out are going to be a few weak spots, such as the siding on your outer leaf. It's going to be super leaky due to the slight gaps between all the planks, and it won't be sealed airtight.

Sealing airtight will benefit you from a sound reduction point of view, if you could get your builder to seal all the joints with caulk from the inside before he puts the insulation and plasterboard on. He could also beef up the inside of the siding with a layer of OSB, then the insulation, then a vapour barrier, then 2 more layers of plasterboard. On the inside you would put your acoustic treatment. Note: The vapour barrier here is super important, don't skip it.

The next weak spot would be your possibly vented roof. Here you would need to leave a continuous ventilation channel (2"/50mm) under your roof deck, assuming you have vents at the eaves. The problem is this will let a lot of sound in. So here you could you could install some battens to the roof joists, fill above the battens with insulation (under the 50mm ventilation gap) install a vapour barrier on the bottom of the battens and attach two layers of plasterboards to the battens. Those plasterboard layers should be connected and caulked to the top plates of the walls, so the walls and ceiling are non broken and continuous.

If you have a warm roof, then that would be even better since you wouldn't need any ventilation. The rigid insulation would go above the roof deck and covered with a waterproof layer such as rubber. This will also help reduce footfall from birds and rain. You could install a couple layers of drywall straight to the underside of the roof deck, between your roof joists and then infill the remaining space with acoustic treatment. The ceiling is one of the most important areas to treat with thick, low density fibreglass insulation, so as much height as you can here is going to help you.

Make sure your builder does either a properly implemented vented roof or a properly implemented warm roof, anywhere in between these two designs and you will have problems with condensation, which will cause you to tear everything down and start again.

The next weak spot will be your window. You'll need some heavy duty glass such as laminated or toughened (tempered), 12mm thick should do. If you want the window to be openable then you will always have air leakage here as you won't be able to seal it. Also the framing of the window should be solid, not hollow or light such as uPVC. The seals are the most vital part of stopping sound coming in.

A solid core door is good here, make sure you have good seals all the way round the perimeter when the door is fully closed. Do not have recessed cavities for handles/locks, use surface mount handles and locks.

Lastly, make sure your builder seals every little gap/crack/hole with a non hardening caulk, especially where the sole plates meet the concrete slab. If he can he should put a rubber strip between the sole plate and the concrete slab, and a bead of caulk under the sole plates before bolting them down to the slab. Then more caulk around the edges. Same with door/window jambs. You're going to need some fresh air ventilation, which means you'll need to make two holes in your sealed up walls, but you'll build some silencer baffle boxes for each hole. These allow the fresh air in without compromising your sound isolation. You may want a mini split air conditioner as well for your cooling/heating.

Hope this helps,
Paul

[ionionalanonalan]

Thanks for the below - that's really helpful. I've read more around this and i'm now planning on doing the following:
- double plaster inside, with offset;
- resilient bars between stud wall and plaster to create separation / decoupling;
- rubber around solid core door.

I'm hoping that's a good amount to do to get myself into a better position than I would have been without spending too much more money.

Thanks for that! So:

- Correct - I mix at a reasonable volume in monitors (so I make some noise, but not crazy amounts and never drums), so I guess I am mostly worried about sound from the outside;
- It's a timber frame build on a concrete slab. I can't figure out the size of the studs etc from the architect/engineer's drawings - bit confusing;
- Weatherboard is wooden planks (so I guess kinda like siding);
- Internal ceiling height is 2400mm.
- Not sure of what kind of roof/venting - from the diagrams it looks like it's just a flat roof on a slight incline.
- One window and one door. I'm getting a solid core door and a fairly small window.

Okay, so since you do not want to spend much more money you won't be able to have a double leaf assembly (a room within a room), however, your isolation needs are much smaller than normal so I would do a non-decoupled double leaf assembly, which means you still have two layers of mass separated by an air gap but the mass layers share the same framing. It should be sufficient for your needs.

From the limited info we have your biggest issues with keeping external noise out are going to be a few weak spots, such as the siding on your outer leaf. It's going to be super leaky due to the slight gaps between all the planks, and it won't be sealed airtight.

Sealing airtight will benefit you from a sound reduction point of view, if you could get your builder to seal all the joints with caulk from the inside before he puts the insulation and plasterboard on. He could also beef up the inside of the siding with a layer of OSB, then the insulation, then a vapour barrier, then 2 more layers of plasterboard. On the inside you would put your acoustic treatment. Note: The vapour barrier here is super important, don't skip it.

The next weak spot would be your possibly vented roof. Here you would need to leave a continuous ventilation channel (2"/50mm) under your roof deck, assuming you have vents at the eaves. The problem is this will let a lot of sound in. So here you could you could install some battens to the roof joists, fill above the battens with insulation (under the 50mm ventilation gap) install a vapour barrier on the bottom of the battens and attach two layers of plasterboards to the battens. Those plasterboard layers should be connected and caulked to the top plates of the walls, so the walls and ceiling are non broken and continuous.

If you have a warm roof, then that would be even better since you wouldn't need any ventilation. The rigid insulation would go above the roof deck and covered with a waterproof layer such as rubber. This will also help reduce footfall from birds and rain. You could install a couple layers of drywall straight to the underside of the roof deck, between your roof joists and then infill the remaining space with acoustic treatment. The ceiling is one of the most important areas to treat with thick, low density fibreglass insulation, so as much height as you can here is going to help you.

Make sure your builder does either a properly implemented vented roof or a properly implemented warm roof, anywhere in between these two designs and you will have problems with condensation, which will cause you to tear everything down and start again.

The next weak spot will be your window. You'll need some heavy duty glass such as laminated or toughened (tempered), 12mm thick should do. If you want the window to be openable then you will always have air leakage here as you won't be able to seal it. Also the framing of the window should be solid, not hollow or light such as uPVC. The seals are the most vital part of stopping sound coming in.

A solid core door is good here, make sure you have good seals all the way round the perimeter when the door is fully closed. Do not have recessed cavities for handles/locks, use surface mount handles and locks.

Lastly, make sure your builder seals every little gap/crack/hole with a non hardening caulk, especially where the sole plates meet the concrete slab. If he can he should put a rubber strip between the sole plate and the concrete slab, and a bead of caulk under the sole plates before bolting them down to the slab. Then more caulk around the edges. Same with door/window jambs. You're going to need some fresh air ventilation, which means you'll need to make two holes in your sealed up walls, but you'll build some silencer baffle boxes for each hole. These allow the fresh air in without compromising your sound isolation. You may want a mini split air conditioner as well for your cooling/heating.

Hope this helps,
Paul