Noise mitigation for music room in a new house extension

[Grater]

Hello all,

I am at the initial stages of planning a house extension, about to engage the services of an architect, before costing, applying for planning permission and all the rest of it.

My girlfriend plays drums, I play various instruments, record and produce, so we intend to include a music/studio room on the ground floor of the two-storey extension.

I realise it is easier to install exterior noise mitigation measures from the ground up, as the room is being built, rather than trying to do it retrospectively. Hence I see this as the one and only opportunity I will have to build the music room I want, after (too many) years of compromise in existing spaces.

Ideally I want a room that I can sit in and near as little outside noise as possible. And, conversely, that the postie can walk past while my girlfriend is bashing away on her kit and be either unaware, or only just aware, of it. Or, even worse, hear me caterwauling

Budget will, of course, be a factor. So I can't afford to appoint a professional acoustic consultant to work hand-in-hand with the architect. However I do understand that the key to exterior noise mitigation is mass.

The plan is not to include large windows, because they would jar aesthetically with the rest of the property. I'm also not keen on the obsession with larch exteriors that domestic architects seem to be hung up on nowadays. Other than that, I'm open minded.

So, before I open negotiations with the architect, I would be grateful for any advice that anyone can offer on suitable materials and methods of construction to mitigate exterior noise, while at the same time hopefully not sending the council building regs peeps into meltdown.

Is it as simple as 'masonry walls as thick as you can make them', or would alternative methods like double-skinned walls with an air gap, or the gap filled with insulation, etc, be better?

I'm hoping that the ceiling insulation and carpet/furniture, air space and ceiling of the room above should deal with noise travelling upwards OK. (Plus, of course, I'll install internal acoustic treatment).

Also, are current standards of floor insulation (polystyrene blocks with concrete poured on top) enough to prevent the kick drum or my bass cabinet from shaking the postie's boots?

Any advice would be much appreciated.

Yours, excited but with a degree of trepidation...

Grater

[James Perrett]

So I can't afford to appoint a professional acoustic consultant to work hand-in-hand with the architect.

You can't afford not to have someone who knows about the subject involved - even if it is to just keep an eye on the builders to stop them taking short cuts that will ruin your isolation. Most builders and architects just don't understand how to create isolated rooms - and I'm talking from personal experience here.

The safest way, if you don't want to engage a specialist at this stage, is to have your architect design and build the outer shell and then for you to engage a specialist to build an inner shell. I did something similar with my current studio although I built the inner shell myself. This is probably the first studio that I've had where the soundproofing actually works - the only external noise that gets through is the sound of low flying Chinooks which sometimes fly directly overhead.

[Mike Stranks]

James is spot-on.

If you don't budget to get someone in who really knows what they're talking about you'll spend a lot of money to very little purpose.

Over the years I've come across architects who I've been assured "know all about the acoustic considerations" only to be unsurprised when the resultant build stopped the passage of unwanted noise as effectively as a sieve. Similarly, when I've raised an eyebrow at the suggestions some 'experts' have come up with about inhibiting sound transmission, my queries have been dismissed on the basis that "they have a degree in engineering and you don't." And guess how effective their solutions were?

This is a highly specialised and complicated subject. Make sure you get genuine specialist advice from someone who's got practical, provable experience of designing/building the sort of space you require.

[Wonks]

What everyone else has said. If you don't have enough budget for an acoustician, then it's unlikely you'll have enough budget to build a proper soundproof room - especially one with enough ventilation to pass building regs.

You can go for lots of mass on the walls and floor, but you'll need a similar amount of mass on the ceiling, which is where it all starts to fall apart in terms of affordable construction. the noise will travel upwards and out. You'll need double doors to form an airlock when you go in. So you'll probably end up with a space that will put people off buying the house if you then try and sell.

A room-in-room construction would be better, as you can then remove the inner room when it comes to selling the house. But this gives you a smaller internal volume with much less height.

You might be better off planning for a single-story extension instead, as anything soundproof is probably going to cost double the budget you thought of.

This is simply the reality of trying to do something like this.

[Watchmaker]

Ditto what everyone else has said. Also bear in mind the extent to which you truly need sound proofing. You don't need dead silence, nor do you want it to be distractingly noticeable. In between is a range of viable options. Know where your happy place is, as well as your line that shall not be crossed, and you can spare yourself chasing diminishing returns.

[Music Wolf]

I concur with the previous posters.

Politicians may bend the constitution whilst Starbucks, Google and Amazon get creative with the tax rules but the laws of physics are sacrosanct.

This may or may not appeal but I would expect that it would be cheaper to purchase a top quality electronic drum kit and a pair of headphones than to achieve the level of sound attenuation your desire by treating the room. Just a thought.

[Grater]

Many thanks for all your replies. You've given me a lot of food for thought.

This may or may not appeal but I would expect that it would be cheaper to purchase a top quality electronic drum kit and a pair of headphones than to achieve the level of sound attenuation your desire by treating the room. Just a thought.

Indeed and a route I have tried a number of times to steer my beloved down. However, much as I show her the many benefits of top electronic kits, her expression reminds me of that on the old school FoH engineers I used to watch when put in front of a Yamaha PM1D back in the early 2000s...

Unfortunately it also doesn't take into account the postie hearing me sing, Or should I say 'sing'.

[Grater]

I've been giving this some more thought and have come to a few conclusions.

Much as I would like to, I'm not building a professional studio, I'm building a domestic extension within which is a 'music room' that has to be converted to a passing facsimile of a bedroom, should we ever want or need to sell the house.

Thus, unfortunately, there will have to be compromises and I have to accept it's not going to be perfect. It's just finding where the sweet spot of those compromises is, somewhere in the middle of a triangle with the corners marked 'acoustic perfection inside and outside', 'aesthetics' and 'cost'.

As I'm right at the start of the process, with not even a pencil mark yet on paper, my current thinking is that the basic starting point is:
1. An asymmetrical room.
2. Windows that are big enough to not make it look like a cell, but small enough to not have half the sound ending up outside. Install secondary glazing within them (to be removable in the future, if necessary).
3. Prioritise mitigating low frequency leakage when looking at materials and construction for the exterior and internal walls.
4. Air vent in exterior wall with a home-made ventilation silencer.
5. Possiblty look at single storey (thanks Wonks) - if not, look making the space betweeen the ceiling and floor of the room above bigger and adding more insulation.
6. An exterior-quality door, with acoustic curtain inside it to be pulled across when the room is in use. (I already have such a curtain, from https://www.vocalboothtogo.co.uk and have been pleased with it).

That's my starting point. Next to find an acoustic consultant for a chat. Preferably one who doesn't charge £500 a minute

[jaminem]

Just looking at the 'acoustic blankets'....
I can see them helping a bit as part of a wider solution i.e room within a room + mass, to damp vocal sounds, and will help them dry up the recording, but can't see them helping you with drums much.
The 'drum blanket' pictures are using them as some sort of early reflection damping rather than having any effect on sound 'proofing'. Note that none of the testimonials come from drum owners....
Having said that I have seen these (well quilted packing blankets which appear to be pretty much the same thing) used to aid separation between kick drum mics and other kit mics, so there's potentially some benefit...
I would also venture that claiming an 80% NRC without stating the frequency range that operates over is moot.

I built an isolation room in my studio, using the room within a room concept, stud frame mounted on rubber and not touching the external walls at all, stuffed voids with Rockwool, then 2 sheets acoustic plasterboard with green glue in between on all walls and ceilings, floating 2 layer chipboard floor with sound deadening sheet, membrane then laminate, secondary glazing and 2 external doors between the main control room and it. Its pretty good 50db attenuation outside at 90db source inside - so you can still hear a bit but not much, not used drums in there but have used fairly loud bass amps and it attenuates quire well although not silent. Most useful thing is the fact that its not attached to my and more importantly my neighbours house.

Most useful stuff Max taught me - Mass/spring/mass and separation!

[stuhutch]

Hi Grater,

I was wondering how far you got with your plans and what route you decided on in the end. It'd be great to hear an update.

Regards
SH

[CS70]

I've been giving this some more thought and have come to a few conclusions.

Something that you may also think of, is also the timing when you want to use the room.

For mixing, I'd say that no reasonable mixing is so (continuously) loud that you need to worry too much. So long you don't blast your speakers at 10pm, and there's no continuous hammering from outside, you'll be generally fine.

That leaves playing and recording loud instruments, that is the noise you make and noise coming from outside (especially low frequencies, which have a lot of energy and travel a lot, but of course also cars, traffic etc.)

Obviously it's a no-no to be loud when there's people all around. In non-lockdown times, that's typically from the afternoon, when everybody gets back to work.

During mornings, however, most people are at work. I often record loud guitars at home usually from 10:00 to 13:00 - not worrying about the amp level, simply because at that time there's nobody in the surrounding houses. During the same time slot, it's also very quiet outside, for the same reason. At least most days: the obvious exceptions is if there's some kind of construction work going on. But it does not happen often.

Obviously it depends on where your house is - if it's in a place where outside noise exist 24/7, or you are in an apartment block with people staying at home all day, you're out of luck (or in for a fight).

But if it's a house in a residential area, you could establish a recording routine with slots a couple of times a week during the morning and that would be very effective - at no cost. Since you're not a commercial studio, usually the challenge is to have material ready for each bi-weekly slot, not that there's not enough time!

My own planning has been of course been throw totally off course by the coronavirus and lockdown-with-family, but in regular times it has served me exceedingly well.

[stuhutch]

Any update on your plans Grater? I'm in the same position as you found yourself re possible extension options and wondered if you had any pearls of wisdom you can offer from your own experience, in addition to the v useful info from the other contributors.

[Eddy Deegan]

As Grater hasn't logged into the forum since early October, there is a possiblity that he has obtained enough information to run with it.

For a domestic space there is much one can do to alleviate noise leakage. I'm building a home studio in my converted roof at present and here are a few things I'm doing which may help. It's not an exhaustive list but hopefully will give food for thought:

For insulation, use at least 100mm of Rockwool RW3. This has a weight of 60Kg/m3 and is one of the more effective materials when it comes to sound absorption.

Note that this may require you to batten out (thicken) the ceiling joists and rafters, as building regulations (certainly in the UK, and probably most places worldwide) require a 50mm air-gap between the insulation and the roof itself for ventilation to avoid condensation buildup. In my case I did not have to do this on the walls, only the ceilings. The guidance I was given by the building regs people was:

• Dormer face & cheeks – 100mm dense mineral wool batts + multifoil & resilient bar over face, then plasterboard.
• Rafters (counter battened to give 50mm air gap to roofing felt) – 100mm dense mineral wool batts + multifoil & resilient bar over face, then plasterboard.
• Flat roof- 50mm air gap to roofing deck, 125mm dense mineral wool batts + multifoil & resilient bar over face, then plasterboard.
  

Note that you may need to push back on your architect and/or builders as many of them default to using lightweight thinner insulation such as Celotex which is thermally efficient but acoustically useless. The Building Regs people were far more understanding on my project when I spoke to them and explained what I was doing.

Unless the floor is solid concrete, install isolation tape between the floor joists and the subfloor above them. In my case the subfloor is 22mm flooring tongue-and-groove board, and I have it sitting on Green Glue Joist Tape.

Do not screw the flooring down through the tape into the joists as this will negate the benefit of the tape. Rather, glue the boards together using a strong wood glue, running a bead along the entire length of all joins and have the floor 'floating' as a single large mass on the isolated joists.

I found that using a glue that foams up a bit while it's drying worked very well as it expands into the joints, although you will need to shave off the foam once it's dry to make it flush with the joints. Leave a small gap around the periphery of the floor.

For the walls and ceiling, use two layers of acoustic plasterboard, with one being at least 15mm thick, separated with a thin layer of green glue noiseproofing compound between the sheets. Ideally each layer of plasterboard should be different thicknesses but for a domestic space that may not matter so much.

The plasterboard should not be screwed directly to the wall, but mounted on flexible supports in the form of resilient bars or genie clips (the latter of which can support standard steel furring channels). Genie clips are more expensive but give an additional 4-6dB of attenuation over resilient bars.

In both cases, the plasterboard screws must only engage with the steel bars and not go through to the wall or studwork. This means that the entire surface has a few mm of 'spring' in it allowing it to flex back and forth.

There should be a 3-to-5mm gap around all edges of each wall (and the ceiling) to prevent them impinging on each other and compromising that movement. This gap should be filled with an acoustic sealant. I'm using green glue sealant for this.

A solid door, the heavier the better, will also help and it should be installed such that it is as airtight as possible (I'll be using compressable rubber strips) when closed.

It also may be possible to get acoustic glass fitted in your windows. This consists of a laminated double-glazed pane which has a layer of polymer sandwiched in it. Depending on the window size and whether or not you need to see out of it as opposed to just having it for illumination, you could also look at adding a layer of Clearsorber to the frame.

In short you're looking at a lot of mass, combined with movement. In total, the plasterboard and insulation in my studio (roughly 60m2 when the area of the walls and ceilings are added up) weighs about 2.5 metric tonnes. It's a lot of work and it's going to cost more to do but it's well worth the effort.

I'm sure others can give more advice, but the above is a good set of practical basics. All links are for illustration only - I'm not recommending any particular source.

[stuhutch]

Eddy,

Thanks so much for your incredible reply. I've only just seen it!!!! I assumed I would've received a notification via email if someone had replied to my post. I'm sure you thought I was incredibly rude to not acknowledge it. Many thanks again.

As Grater hasn't logged into the forum since early October, there is a possiblity that he has obtained enough information to run with it.

For a domestic space there is much one can do to alleviate noise leakage. I'm building a home studio in my converted roof at present and here are a few things I'm doing which may help. It's not an exhaustive list but hopefully will give food for thought:

For insulation, use at least 100mm of Rockwool RW3. This has a weight of 60Kg/m3 and is one of the more effective materials when it comes to sound absorption.

Note that this may require you to batten out (thicken) the ceiling joists and rafters, as building regulations (certainly in the UK, and probably most places worldwide) require a 50mm air-gap between the insulation and the roof itself for ventilation to avoid condensation buildup. In my case I did not have to do this on the walls, only the ceilings. The guidance I was given by the building regs people was:

• Dormer face & cheeks – 100mm dense mineral wool batts + multifoil & resilient bar over face, then plasterboard.
• Rafters (counter battened to give 50mm air gap to roofing felt) – 100mm dense mineral wool batts + multifoil & resilient bar over face, then plasterboard.
• Flat roof- 50mm air gap to roofing deck, 125mm dense mineral wool batts + multifoil & resilient bar over face, then plasterboard.
  

Note that you may need to push back on your architect and/or builders as many of them default to using lightweight thinner insulation such as Celotex which is thermally efficient but acoustically useless. The Building Regs people were far more understanding on my project when I spoke to them and explained what I was doing.

Unless the floor is solid concrete, install isolation tape between the floor joists and the subfloor above them. In my case the subfloor is 22mm flooring tongue-and-groove board, and I have it sitting on Green Glue Joist Tape.

Do not screw the flooring down through the tape into the joists as this will negate the benefit of the tape. Rather, glue the boards together using a strong wood glue, running a bead along the entire length of all joins and have the floor 'floating' as a single large mass on the isolated joists.

I found that using a glue that foams up a bit while it's drying worked very well as it expands into the joints, although you will need to shave off the foam once it's dry to make it flush with the joints. Leave a small gap around the periphery of the floor.

For the walls and ceiling, use two layers of acoustic plasterboard, with one being at least 15mm thick, separated with a thin layer of green glue noiseproofing compound between the sheets. Ideally each layer of plasterboard should be different thicknesses but for a domestic space that may not matter so much.

The plasterboard should not be screwed directly to the wall, but mounted on flexible supports in the form of resilient bars or genie clips (the latter of which can support standard steel furring channels). Genie clips are more expensive but give an additional 4-6dB of attenuation over resilient bars.

In both cases, the plasterboard screws must only engage with the steel bars and not go through to the wall or studwork. This means that the entire surface has a few mm of 'spring' in it allowing it to flex back and forth.

There should be a 3-to-5mm gap around all edges of each wall (and the ceiling) to prevent them impinging on each other and compromising that movement. This gap should be filled with an acoustic sealant. I'm using green glue sealant for this.

A solid door, the heavier the better, will also help and it should be installed such that it is as airtight as possible (I'll be using compressable rubber strips) when closed.

It also may be possible to get acoustic glass fitted in your windows. This consists of a laminated double-glazed pane which has a layer of polymer sandwiched in it. Depending on the window size and whether or not you need to see out of it as opposed to just having it for illumination, you could also look at adding a layer of Clearsorber to the frame.

In short you're looking at a lot of mass, combined with movement. In total, the plasterboard and insulation in my studio (roughly 60m2 when the area of the walls and ceilings are added up) weighs about 2.5 metric tonnes. It's a lot of work and it's going to cost more to do but it's well worth the effort.

I'm sure others can give more advice, but the above is a good set of practical basics. All links are for illustration only - I'm not recommending any particular source.