Cellar soundproofing project

[SoWhat]

Greetings,

The fact is, you should bolt the sole plates down into the concrete

This.

You should run a bead of non-hardening caulk on the plates before affixing them to the concrete, then as Paul suggested, seal at the edges.

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?

Along with the air, sound will travel in and out. You will defeat the isolation without silencers/baffles. Also, this does nothing to address humidity levels. Your gear lives best in spaces with constant humidity (40-45% ideally). Also, when you're working, that sort of humidity level is very comfortable to be in for long periods.

Paul and DanDan have given you great advice. Follow it and you will have a good space.

All the best,

Paul

[David51]

Yes, don't worry, I take your advice into consideration, so much so that I have abandoned my basic project to turn to the one recommended here.

But before I start, given the little space I have, and the not unlimited means, I really want to be 100% sure.

On this subject, there are still three last points on which I would like to have your opinion, and I think I'll get started:

1) The vertical uprights on which the walls are scoured, we agree that at the bottom they are fixed to cleats screwed in the floating concrete slab, but at the top, I also fix them to cleats fixed on my concrete ceiling, or I fix them to a kind of frame detached from the ceiling (I think it's more logical no, but the rigidity of the whole doesn't seem to be very good, hence my question)? (cf the two pictures 1 and 2)

2) For the cleats screwed to the floor on the slab, do I leave a space with the acroteria (5cm type), or can I glue them to the acroteria (let's say I screw them 1cm from the acroteria so that they are not in direct contact), knowing that they are insulated from my foundations by an insulating material? (see the two images 3 and 4). Because the more I move them away, the more I lose in surface....

3) Finally, for my staircase, it doesn't matter if there is a cut-out in my stall for access, and I just insulate the access hatch? because I won't be able to have a door in my stall otherwise I lose a monstrous surface area.

Thank you in advance for your answers.

[DanDan]

A bit late now but anyway, what is a Cleat? Acroteria?
I am not sold on the idea of bolting the floor plate to the concrete. Given modern glues why diminish the isolation? If there is a substantial risk of movement there ways other than penetration and contact surely?

[Paulus87]

Yes, don't worry, I take your advice into consideration, so much so that I have abandoned my basic project to turn to the one recommended here.

But before I start, given the little space I have, and the not unlimited means, I really want to be 100% sure.

On this subject, there are still three last points on which I would like to have your opinion, and I think I'll get started:

1) The vertical uprights on which the walls are scoured, we agree that at the bottom they are fixed to cleats screwed in the floating concrete slab, but at the top, I also fix them to cleats fixed on my concrete ceiling, or I fix them to a kind of frame detached from the ceiling (I think it's more logical no, but the rigidity of the whole doesn't seem to be very good, hence my question)? (cf the two pictures 1 and 2)

2) For the cleats screwed to the floor on the slab, do I leave a space with the acroteria (5cm type), or can I glue them to the acroteria (let's say I screw them 1cm from the acroteria so that they are not in direct contact), knowing that they are insulated from my foundations by an insulating material? (see the two images 3 and 4). Because the more I move them away, the more I lose in surface....

3) Finally, for my staircase, it doesn't matter if there is a cut-out in my stall for access, and I just insulate the access hatch? because I won't be able to have a door in my stall otherwise I lose a monstrous surface area.

Thank you in advance for your answers.

The new ceiling timbers (joists) will rest on your new walls top plates, ideally exactly above the upright timbers (studs). Screw/nail them or use joist hangers. Make sure there is a gap between the new ceiling and your concrete ceiling. As big a gap as you are willing to lose. Same for your new walls.

You could also build the whole thing inside out, which would mean your new framing will have the plasterboard on the outside, rather than the inside. Then you can use the open spaces between the timbers for acoustic treatment. This will save space, but decrease your isolation... swings and roundabouts.

I do not understand what you mean when you say "For the cleats screwed to the floor on the slab, do I leave a space with the acroteria (5cm type), or can I glue them to the acroteria (let's say I screw them 1cm from the acroteria so that they are not in direct contact), knowing that they are insulated from my foundations by an insulating material? (see the two images 3 and 4). Because the more I move them away, the more I lose in surface...."
I don't think you mean an acroteria... that is an ornamental piece placed on a plinth of monuments or important buildings.

Perhaps you mean a plinth? A concrete "lip" ? and why are cleats needed?

Whatever it is you mean, just keep it simple: the bottom plates of the new walls just need to be bolted straight down into your concrete floor. Use caulk/rubber under them before you bolt them down and then seal along the edges with caulk. You may have used some insulation between the old concrete and the walls and the new concrete, but it is not decoupling the new concrete floor, just treat your existing concrete walls and the whole floor as one single connected shell. As I said, it does not matter that the new walls are built on top of your concrete slab because the concrete slab is very very dense and damped by the earth.

Regarding the stair case and the hatch... what do you mean by stall?

Je parles un petit peu français, mais je pense que ce sera plus difficile pour moi de comprendre le vocabulaire en français, qu'en anglais, desolé!

Paul

[Paulus87]

A bit late now but anyway, what is a Cleat? Acroteria?
I am not sold on the idea of bolting the floor plate to the concrete. Given modern glues why diminish the isolation? If there is a substantial risk of movement there ways other than penetration and contact surely?

Dan, given that it's a fairly small space it could work... but I personally would rather not risk it and bolt it. I am not aware of the building regs on this but I would be surprised if it would pass regs by just being glued and not bolted.

Also, really what difference is it going to make in terms of isolation? If he glues it, it will still be in contact with the slab. The slab is far from his weakest point in the isolation envelope... the concrete is thick and dense and damped by the earth... hard to beat.

It is rarely ever needed to float the floor and if a floated floor is needed then it needs to be done properly (expensive, plus a mathematical nightmare) with proper springs/resilient devices to even be effective. Either do it properly or not at all.

The two leaves connected at the concrete base is the least of his worries in my opinion.

Paul

[DanDan]

DOH, in my mind I still had the Neoprene between Floor plate and concrete. Also between ceiling plate and whatever is above. So plate (is that the right term) glued to neoprene glued to concrete.
Given a Kick drum I would think any extra bit of isolation from from the floor would be worth availing of.

[Paulus87]

DOH, in my mind I still had the Neoprene between Floor plate and concrete. Also between ceiling plate and whatever is above. So plate (is that the right term) glued to neoprene glued to concrete.
Given a Kick drum I would think any extra bit of isolation from from the floor would be worth availing of.

I think in order for the neoprene to provide decoupling it would need to be calculated to provide damping at least an octave below whatever frequency occurs in the room when the kick drum is struck, as well as the force from the impact. A bit like trying to calculate sorbothane hemispheres for loudspeaker decoupling - too high and it does nothing, too low and it makes things worse. I don't know about you, but that's way out of my league in terms of mathematical knowledge.

What the neoprene will do, though, is make a nice seal and help to fill in any imperfections in the slab and sole plates. I'm still not keen on the idea of only glueing all the walls to neoprene though.

Paul

[David51]

DanDan, the 4 acroteria constitute the concrete belt that rests on my new slab and which is joined to it via metal reinforcements. Their function is to consolidate the foundations since I had to dig under the underside of the foundations. Between these foundations and the acroteria there is a strip of insulating material.

Paul,

1) for the new ceiling I understood perfectly thank you .

2) as explained above, the acroterias are the concrete belt that reinforce the foundations. This belt and my new slab are one and the slab is insulated underneath with polystyrene, and around the edges, at the level of the acroteria so that they are not in direct contact with the foundations, by an insulating material. I perfectly understood that my cinder block walls and my old floor (under the slab) must be considered as a whole, and my slab and my box as another whole. My only question is: so, since the acroteria and the slab are one, can I glue as much as possible my lower slabs to the acroteria, or even on top of them, which would allow me to gain a significant surface area (I think you will answer positively because as said above: acroteria + slab = 1).

3) currently I have in my concrete ceiling a cut-out for the passage of the staircase leading to my cellar. If I want to access my new stall, I would also have to make a cutout in the new ceiling which will therefore remain open at all times. Only the initial cellar hatch will allow me to close my cellar (and not a second door to the stall). Is the hole in the stall disturbing to you?
David

[Paulus87]

DanDan, the 4 acroteria constitute the concrete belt that rests on my new slab and which is joined to it via metal reinforcements. Their function is to consolidate the foundations since I had to dig under the underside of the foundations. Between these foundations and the acroteria there is a strip of insulating material.

Paul,

1) for the new ceiling I understood perfectly thank you .

2) as explained above, the acroterias are the concrete belt that reinforce the foundations. This belt and my new slab are one and the slab is insulated underneath with polystyrene, and around the edges, at the level of the acroteria so that they are not in direct contact with the foundations, by an insulating material. I perfectly understood that my cinder block walls and my old floor (under the slab) must be considered as a whole, and my slab and my box as another whole. My only question is: so, since the acroteria and the slab are one, can I glue as much as possible my lower slabs to the acroteria, or even on top of them, which would allow me to gain a significant surface area (I think you will answer positively because as said above: acroteria + slab = 1).

3) currently I have in my concrete ceiling a cut-out for the passage of the staircase leading to my cellar. If I want to access my new stall, I would also have to make a cutout in the new ceiling which will therefore remain open at all times. Only the initial cellar hatch will allow me to close my cellar (and not a second door to the stall). Is the hole in the stall disturbing to you?
David

Okay understood, yes you can attach the new walls to whichever part of the slab you want. Just space them out from the existing walls at the maximum distance you are allowing.

Regarding the hatch, the stair case folds down into the hatch and then you can fold it back up once you are inside? If so, is it not possible to build a second hatch attached to your new ceiling which remains open when you are not in the room, then once you are inside the room you can fold the stairs away and close the second hatch?

Sorry if I have completely misunderstood

Paul

[David51]

Hello everyone, sorry for the late answer, unfortunately I didn't have the possibility to access my computer this weekend.

Unfortunately no, the staircase is a wooden staircase, "fixed" (not retractable). And moreover you will see thanks to the drawing below, that it falls right into the famous acroteria (I can fix that by making a quarter turn on the old staircase).

I think I'm going to be condemned to scrap a big space, and put a door in my new box...

Unless you still have some good advice to share with me.

[Paulus87]

Hello everyone, sorry for the late answer, unfortunately I didn't have the possibility to access my computer this weekend.

Unfortunately no, the staircase is a wooden staircase, "fixed" (not retractable). And moreover you will see thanks to the drawing below, that it falls right into the famous acroteria (I can fix that by making a quarter turn on the old staircase).

I think I'm going to be condemned to scrap a big space, and put a door in my new box...

Unless you still have some good advice to share with me.

Yes, unfortunately all your new isolation efforts will be in vain unless you find a solution to seal up the staircase hatch in both the outer and inner leaves.

Paul

[David51]

Hello everyone, I hope you are doing well given the health context?

I came to give you a little feedback on my work, I also wanted to thank you all for the precious advice you gave me and which helped me a lot.

Here is the result in pictures, you can compare with the pictures of the beginning of the construction site at the beginning of this topic.

I have a few questions:

1) I have to make the doors "soundproof", I thought of putting a seal all around the door frame (I'll add a wooden strip at the bottom to completely close the frame) that would be crushed by the door when closing, and upholster the doors with rock wool. What do you think about it?

2) Also what do you think of the thickness of the wall that separates the room from the staircase? I am advised to re-insulate

3) I am also advised to "coffer the staircase" (close the steps) without forgetting to fill it with rock wool.

Finally I'm going to glue the black and white foams you see in the picture to the ceiling, and put the black corner foams at the corners, and make acoustic absoprtion panels.

Thank you in advance for your answers and see you soon.

[gullfo]

looking good. definitely add insulation into the framing (and beef up it needed) and consider adding absorbers into the stairwell as well since that can effectively become a noisy place - which will transmit into the adjoining spaces.

[David51]

looking good. definitely add insulation into the framing (and beef up it needed) and consider adding absorbers into the stairwell as well since that can effectively become a noisy place - which will transmit into the adjoining spaces.

Thank you very much (ps don't mind I haven't cleaned and repainted everything yet).

Okay, I made a drawing of how I'm going to put the seal on the door frame (first 3 pictures).

1) In Green it's the wood strip that I will fix to close the frame (no gap between the bottom of the door and the floor), and in Orange the seal. Let me know if it seems coherent?

Vue isométrique porte.png

porte ouverte.png

porte fermée coupe.png

2) For the seal I used a P-profile seal (see picture).

Joints.jpg

3) For the bottom of the door I would like to use a kind of anti-noise door bottom (see picture).

Bas porte.jpg

Also I forgot: I made myself silencers for my mechanical ventilation, it works very well, I can't be heard outside very much (not at all when traffic noise or other). I have actually gained 40 decibels compared to before insulation, but in the house I can still be heard since the doors are not insulated and the stairwell is a real reasoning box. Do you think that I need in addition to insulate the doors, increase the insulation of my wall between the room and the stairwell?

Silencieux vmc.jpg

Finally I was thinking of padding the doors like this with 5cm thick high density foam:

https://www.youtube.com/watch?v=gKTFhCQ0W-s

Is there something more efficient or is it a good solution?

[gullfo]

in general, foam is limited in it's range of frequencies it will absorb effectively. if you can building 3-4" (75-100mm) thick semi-rigid insulation type absorbers for the doors, and at each end of the stair case, plus two more on the ceiling above stairs if you have the head room.