Cellar soundproofing project

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David51
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Cellar soundproofing project

Post by David51 »

Greetings, everyone. My name is David and I come from Reims/France

I hope you are well under the circumstances?

I've come to ask your knowledge because I'd like to turn my cellar into a studio. However, there are a few things I would like to discuss with you:

1) the dimensions are 3.6*3.5 by 2.07m high. the walls are made of cinder blocks and the floor is made of dirt.

Is the height not a problem? I would like to pour a "floating" slab with peripheral insulation, for that I wanted to extract some dirt but it seems to me that the foundations are not very far from the ground level (see the isometric view of the cellar and the cellar detail view).

2) Once this difficulty of the slab had passed, I had considered to cover my walls with soundproofing plasterboard, and between the blocks and this sheet, to put rock wool (for thermal and acoustic insulation). I suppose it is necessary to do the same thing with the ceiling? On the other hand, for the slab I had considered laying parquet and possibly putting my drumset on a wooden platform to limit contact with the slab as much as possible. (see Soundproofing cellar).

3) Finally I would cover the new walls with acoustic insulation panels.

I am waiting for your feedback to see if this project seems feasible to you.

Don't hesitate to ask me your questions, I can also share pictures.
David51
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Re: Cellar soundproofing project

Post by David51 »

Hello everyone, I'm here to tell you about the progress of my project.

The material that was under the footings of the foundations was in fact "clean concrete", it is a very poor concrete that is deposited on the foundation trenches so that they can be poured on a clean surface.

So I was able to remove rat dirt from the foundations, on 50cm and thus gain height under the ceiling. A plastic film was placed on the freshly poured floor, as well as 40mm of extruded polystyrene and the concrete slab was poured over it.

Metal pins were placed on the periphery of the slab, then acroteria were cast on these metal pins. A strip of acoustic insulation was deposited on the entire perimeter of the acroteria. (cf photo)

Now I am going to tackle the insulation: I wanted to create cleats made of mdf (medium density fiberboard) and acoustic foam, i.e. 10mm mdf - 40 mm acoustic foam - 10mm mdf, all glued together. I fix all this to the walls, put polyurethane foam plates in between, and screw my (blue) acoustic plasterboard plates on top. For the ceiling and the floor, I put horizontal cleats with also a strip of PU foam to uncouple my insulation from the floor and the ceiling.

What do you think about this? Do you think it's a good idea or do you have some advice for me? Thank you in advance.
Paulus87
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Re: Cellar soundproofing project

Post by Paulus87 »

David51 wrote:Hello everyone, I'm here to tell you about the progress of my project.

The material that was under the footings of the foundations was in fact "clean concrete", it is a very poor concrete that is deposited on the foundation trenches so that they can be poured on a clean surface.

So I was able to remove rat dirt from the foundations, on 50cm and thus gain height under the ceiling. A plastic film was placed on the freshly poured floor, as well as 40mm of extruded polystyrene and the concrete slab was poured over it.

Metal pins were placed on the periphery of the slab, then acroteria were cast on these metal pins. A strip of acoustic insulation was deposited on the entire perimeter of the acroteria. (cf photo)

Now I am going to tackle the insulation: I wanted to create cleats made of mdf (medium density fiberboard) and acoustic foam, i.e. 10mm mdf - 40 mm acoustic foam - 10mm mdf, all glued together. I fix all this to the walls, put polyurethane foam plates in between, and screw my (blue) acoustic plasterboard plates on top. For the ceiling and the floor, I put horizontal cleats with also a strip of PU foam to uncouple my insulation from the floor and the ceiling.

What do you think about this? Do you think it's a good idea or do you have some advice for me? Thank you in advance.
Hi,

I'm glad you were able to fix your floor!

I am not sure what you would like to achieve with your proposed wall assembly - you already have cinder block walls, the MDF sandwich is not likely to provide much more sound reduction, especially if you attach it to the wall directly. Acoustic foam really has no place in the isolation assembly, or acoustics for that matter! I really cannot think of a situation where I would use acoustic foam for anything in a studio, despite all the marketing.

In short - your proposal is an unknown, I have no idea what it will achieve and can see a lot of potential issues with it. Tell us what you need in terms of:

- sound reduction - do you even need "sound proofing"? If so, by how many decibels?
- what is the purpose of the room? Control room and or tracking room?

Paul
Paul
David51
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Re: Cellar soundproofing project

Post by David51 »

Paulus87 wrote:
- 1) sound reduction - do you even need "sound proofing"? If so, by how many decibels?
- 2) what is the purpose of the room? Control room and or tracking room?

Paul
Hello Paul,

First of all, thank you for taking the time to read and answer my topic.

1) This 12.5m² room is intended to become my rehearsal room for my drum practice. So I didn't push the study in order to determine the exact amount of decibels to reduce, but I assume that who can do the most can do the least, so the maximum will be the best (of course within a reasonable budget, I'm not going to oversize either).

2) my fears: for the "high frequencies" (especially cymbals and snare drum) I don't worry too much since I'm under the floor, for the "low frequencies", and especially the bass drum, I'm very afraid of solidary transmissions, especially since one of the walls is common with my neighbor's garage.

To give an example, when I would pick or ground during the work, you would hear/"feel" them all over the house as if you were in the basement.
Paulus87
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Re: Cellar soundproofing project

Post by Paulus87 »

I see.

Well unfortunately the only way to reach that level of isolation down to such low frequencies takes up considerable space.

You could either build a new set of walls and ceiling inside your current space from concrete blocks/block and beam or a traditional timber frame with drywall/plywood/osb etc layers.

Whichever method you choose you’ll need to make sure the new inner shell is not touching the existing space in anyway other than the floor. The bigger the gap between the existing shell and the new shell which you are yet to build the better isolation you’ll achieve, to be precise, as the gap gets bigger the lower down the frequency spectrum you’ll be able to Isolate down to. This gap must be filled with cheap low density insulation.

You should expect to lose between 6-12” all the way round the perimeter and ceiling of your current space. If you are only going to have a drum kit in there then you may still have enough space, it will be quite a violent sounding room though due to the proximity of the boundaries to the drums, but it would be fairly quiet outside of the room.

By applying mass and rigid insulation and acoustic foam etc directly to the walls without any decoupling will only get you so far - since there will still be a physical connection to the rest of the house. You can expect to deaden some high end and high mids, but the low end will just transfer straight through like a knife through butter, and low end is your main issue.

Paul
Paul
David51
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Re: Cellar soundproofing project

Post by David51 »

I made a diagram like this no ambiguities

I thought I would place my cleats against the wall, vertically spaced 600mm apart, then up and down with between floor and ceiling and the two horizontal cleats, a strip of PU foam (to uncouple). Between each slat: PU foam (by the way, I saw that some of them didn't cover all the space between the slats as on the left picture, is this a subtlety?).

After soundproofing plasterboard (blue) and above all still foams. (and of course I repeat the operation above and below for ceiling and floor).

What do you think about it? I see this kind of process on many sites specialized in sound insulation.

(ps: I've zoomed in on my cleats: mdf-insulating foam-mdf)
SoWhat
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Re: Cellar soundproofing project

Post by SoWhat »

Greetings,

As Paul noted:
Acoustic foam really has no place in the isolation assembly, or acoustics for that matter! I really cannot think of a situation where I would use acoustic foam for anything in a studio, despite all the marketing.
Likewise, killing low frequencies (don't forget, your snare is actually a lower frequency than you realize; think about how you can "feel" a solid rimshot) is going to be your main objective (I'm a drummer too). Paul's suggestion of how to proceed is your best bet, although your space will become smaller. Methinks it will also be less expensive than your own proposal (it's also much less fussy construction).

All the best,

Paul (a different one)
Paulus87
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Location: Wales, UK

Re: Cellar soundproofing project

Post by Paulus87 »

David51 wrote:I made a diagram like this no ambiguities

I thought I would place my cleats against the wall, vertically spaced 600mm apart, then up and down with between floor and ceiling and the two horizontal cleats, a strip of PU foam (to uncouple). Between each slat: PU foam (by the way, I saw that some of them didn't cover all the space between the slats as on the left picture, is this a subtlety?).

After soundproofing plasterboard (blue) and above all still foams. (and of course I repeat the operation above and below for ceiling and floor).

What do you think about it? I see this kind of process on many sites specialized in sound insulation.

(ps: I've zoomed in on my cleats: mdf-insulating foam-mdf)
I do not have experience with the assembly you are proposing, so I really cannot comment on how effective it will be. But since you asked for my thoughts:

Despite the use of PU foam it will not completely decouple at all frequencies, it will probably only be effective at decoupling in a very narrow range. I just don't think it will work the way you hope it will, despite what you may have seen on the internet.

The sound block plasterboard (blue) is really not necessary, and likely a lot more expensive than 2 layers of standard plasterboard. All that matters is surface density, whichever has the most surface density for the lowest price will be the superior product in terms of sound reduction.

I think you will spend a lot of money and effort trying to do this and you may get average results. That might be enough for you, in which case that's great. But it is definitely not going to isolate low frequency as much as a fully decoupled double leaf assembly with suitable cavity.

Paul
Paul
DanDan
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Re: Cellar soundproofing project

Post by DanDan »

Decoupling the floor from Kick Drum transmission to the walls and underneath to next door would be difficult. Why not decouple the Kick drum from the floor. A floating drum platform.
The principles of wall and ceiling and indeed any sound proofing are well known and published. There are many guides as to how to achieve them.
I don't know of anybody using foam. The air gap of any Mass Air Mass sound stopping system is best filled with light fibre, touching all around but not compressed. Support it with wires or whatever to prevent it sagging downwards over the years.
David51
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Re: Cellar soundproofing project

Post by David51 »

You're talking about building new walls that at no time, except for the ground, would be in contact with the existing cinder block (or concrete) walls, I get it.

But if you look carefully, that's what I intend to do, at no time will my walls come into contact with the cinder block walls, except on the fixing cleats which will be prepared to transmit the minimum vibrations.

1) What you would advise me to do is to put partitions as far away from my walls as possible, but in this case how do I fix them? with floor and ceiling brackets?

2) Also the polyurethane foam is not appropriate according to you, you talk about low density materials, what is the best material according to you (I've heard a lot about rock wool).

3) Another solution exists and less expensive than the phonic plasterboard (which is a high density placo) is to double the thickness of classic plasterboard and put it in quincunx, what do you think of that. I read everywhere that it had a better result for less money.

Ps: DanDan, I've done a lot of research on the subject during my research, and almost all the cellars are prepared according to the process I've explained to you.
If you are interested I can pass you the links of the websites with example?
SoWhat
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Re: Cellar soundproofing project

Post by SoWhat »

The easiest way to explain this:

Frame out new walls with a bottom plate (or sill, depending on your terminology, same thing), studs, and top plate, and joists for the inner ceiling. The bottom plate is affixed to the concrete exactly as if you were building a house, nothing fancy. Your new inner walls and inner ceiling will be completely decoupled from the existing outer structure. Plasterboard the inside of the new wall and put cheap fluffy insulation in the cavity between the existing (now, outer) wall and the new inner wall. This is by far the best and most cost effective method.

As mentioned earlier, the internet is full of costly, ineffective methods for studio construction, especially "soundproofing."

All the best,

Paul
DanDan
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Re: Cellar soundproofing project

Post by DanDan »

As Paul said, but if I may recommend a detail.
I would insert a layer of Neoprene under the floor stud plate and above the ceiling stud plate. Glue them in place. No nails or screws to damage the isolation.
The best fibre to fill the air gap is the cheapest! There is no acoustic benefit to dense expensive batts. Isover have tested and shown that a full fill of light fibre (Partition Roll/Blanket) works best.
It should touch the sides to damp vibration in the plasterboard, but not be compressed. Make sure it cannot sag downwards over the years by weaving some light wire or string through it.
There are some heavier plasterboards which have much higher Transmission Loss numbers. Typical plasterboard is 34Rw, somebody, Knauf? has a 40dB one.
Two layers of regular plasterboard will also do 40dB so do the Arithmetic re cost.
David51
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Re: Cellar soundproofing project

Post by David51 »

DanDan wrote:As Paul said, but if I may recommend a detail.
I would insert a layer of Neoprene under the floor stud plate and above the ceiling stud plate. Glue them in place. No nails or screws to damage the isolation.
Indeed this is the question I was going to ask. Thank you for answering it spontaneously :).

On the other hand, you talk about gluing the insulation layer between the battens that will fix the frame, and the floor and ceiling, but to fix this battens + insulation on the floor and the ceilling, you also plan to glue them? I'd rather put dowels in my cinder block walls and screw the assembly in place. I'm afraid that glue with time and successive vibrations will not be as effective :/

My second question concerns the floor, would it not be relevant to do the same principle? For example, I square my concrete slab with a wooden reinforcement on which I fix my floor (same for the ceiling)? Or is it oversized and I can directly put a parquet floor for example and the vibrations transmitted by the solid state will be attenuated in spite of everything?
Paulus87
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Re: Cellar soundproofing project

Post by Paulus87 »

David51 wrote:
DanDan wrote:As Paul said, but if I may recommend a detail.
I would insert a layer of Neoprene under the floor stud plate and above the ceiling stud plate. Glue them in place. No nails or screws to damage the isolation.
Indeed this is the question I was going to ask. Thank you for answering it spontaneously :).

On the other hand, you talk about gluing the insulation layer between the battens that will fix the frame, and the floor and ceiling, but to fix this battens + insulation on the floor and the ceilling, you also plan to glue them? I'd rather put dowels in my cinder block walls and screw the assembly in place. I'm afraid that glue with time and successive vibrations will not be as effective :/

My second question concerns the floor, would it not be relevant to do the same principle? For example, I square my concrete slab with a wooden reinforcement on which I fix my floor (same for the ceiling)? Or is it oversized and I can directly put a parquet floor for example and the vibrations transmitted by the solid state will be attenuated in spite of everything?

The neoprene on the bottom and top plates is a good idea but not for decoupling purposes in my opinion, though that will help a little in that regard. The fact is, you should bolt the sole plates down into the concrete anyway which will negate any decoupling achieved via the neoprene.

But, the main reasons why I would use it: It helps to ensure a good air tight seal between the sole plate and the floor by filling in any irregularities in the concrete and timber. The perimeter will still need to be caulked all the way round to completely seal it.

I personally don't think it's necessary to use neoprene on the top plates, as again your new ceiling joists will be resting directly on top of those plates and nailed/screwed down into them.

Dowels directly into the cinder block walls to hold your new frame? Well, there would be absolutely no point building a new decoupled frame at all if you were going to then destroy that decoupling by making a physical connection to the cinder blocks again.

Here's what you need to remember: your current walls and ceiling are one leaf (outer leaf) and the new timber structure that we are advising you to build is also one leaf (inner leaf). They need to remain completely separate, free standing and unconnected. No physical connection between them at all. The only place they will be touching is the ground, but that's okay since the ground in your case is an infinitely damped and massive concrete slab on grade.

For your floor, is the concrete slab insulated? was a damp proof membrane installed before the concrete was poured? If yes, then you can simply put an underlayment down and put your parquet floor directly on top.

Before you build the new inner leaf (your timber frame and plasterboard) you should seal up any and all the gaps/cracks in your current cinder block walls/ceiling. You can just do this with a non hardening caulk. If the blocks are somewhat porous, then you can also paint them to seal up any tiny gaps.

One thing we haven't spoken about yet is air conditioning and ventilation, which you will absolutely need. Which is one of the only times you will make penetrations in your inner and outer leaves, but if designed and executed correctly it will not be a problem.

Paul
Paul
David51
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Re: Cellar soundproofing project

Post by David51 »

I took the liberty of making another drawing to see if we agree. Small precision: the structure, I didn't have fun making the floor cleats, then the vertical cleats, then the cleats on which the ceiling will be fixed and finally the plasterboard. I just made a box by uncoupling what needs to be uncoupled so that we can make a final decision on the concept.

Next:

1) For your floor, is the concrete slab insulated? was a damp proof membrane installed before the concrete was poured? If yes, then you can simply put an underlayment down and put your parquet floor directly on top.

Before pouring the concrete slab, we actually laid a plastic sheet to prevent rising damp, then a 40 mm layer of extruded polystyrene and finally 80/100 mm of fiber concrete. The acroters are attached to the slab, but insulated from the concrete footings by a layer of insulating material about 5mm thick. My slab is therefore insulated underneath and on the periphery.

2) One thing we haven't spoken about yet is air conditioning and ventilation, which you will absolutely need. Which is one of the only times you will make penetrations in your inner and outer leaves, but if designed and executed correctly it will not be a problem.

In my basement, I have an opening in the cinder block wall overlooking my garden. Above the basement there is a brick column, when I opened it the other day and put my hand in it I feel a draught going upwards, I think this column was originally intended for the old boiler, a pipe that was supposed to go up to the roof level. And by drilling my concrete slab (the ceiling of the basement) I can give onto this "air column, empty".
I had left to install a vmc, but in the end I think that a natural ventilation could be possible, so a pipe that would open in this wooden construction and that would go in this column by crossing the upper slab, and a pipe that comes from the cut in the cinder block wall and that opens in my wooden structure. and moreover these two "arrival and exit" are facing each other. What do you think about it?

3) Also, my access to the cellar is through a trap door (see drawing) and I am adapting the old staircase to reuse it.

It is absolutely necessary that the staircase opens in the cellar, then I open a door to enter in my wooden structure, or I leave a cutout in the wooden structure where the staircase will open, and of course the trap door will be closed at the top.

In the meantime, thank you all for the time you spend on my project, it's very nice.
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