Submitted by Snoo_9017 t3_zuxy5o in DIY

Hey,

I was planning to go dot and dab, but then I become aware of the downsides of dot and dab in terms of sound acoustics, basically, the hollow space between drywall and wall acts like a drum, I do still need to flatten walls and as well achieve a bit better acoustics, the wall separates me from my neighbor.

so I was wondering, why not add adhesive 1200x1200 area for the whole drywall? I know that will double the costs, but since plaster has good acoustic values, it will simply improve the acoustic properties further, But I'm curious why I can't find such an example, is there a problem with the approach that I'm not seeing yet?

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Update: Based on u/Amazing-Voice-122's comment I wanted to mention my whole plan, In addition to the one above, I will also glue another layer of drywall with carpet glue(https://www.youtube.com/watch?v=BW2ce3H-sAo). Then a question may rise why not use carpet glue for the first layer as well, there comes my stupidity buying 20 drywall adhesives and spending 370 eur for it, and it has been more than a month since I ordered it, so I cannot return it back. Then I realized dot and dab will do much worse in terms of acoustics, then I realized there is also carpet glue, I got 4L for 33 eur, approx. 1L for 1200x2400 sheet, which would be the dampening layer between two drywalls.

So I'm adding 2 x 12,5 mm drywalls sandwiched with carpet glue and sticking to the wall with drywall adhesive a layer of 1 - 2 cm, so in total it would be 5cm of layer maximum, I'm also counting every cm because I don't want to suffer from space, since rooms aren't that large too.

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Comments

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bobsixtyfour t1_j1mmt09 wrote

Do you know if the existing wall has insulation? If not... then maybe the best option is to tear down all the drywall, add sound dampening insulation to the wall cavity, and then re-drywall it up with whatever number of layers you feel like.

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Amazing-Voice-122 t1_j1lwxls wrote

Just adding another layer of drywall won't help very much. A better but more expensive method would be to put up another wall with acoustic insulation between and no connecting framing between the two walls that would conduct sound vibrations. A gap of an inch or two between them would be sufficient.

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specialk879 t1_j1mv2mh wrote

Adding another layer of drywall will help, alot. It would be better to use acoustic plasterboard however

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Snoo_9017 OP t1_j1mdvt4 wrote

u/Amazing-Voice-122 I added an update to address your suggestion, The room width is 265cm, so I'm going to cut that to 260cm, but I don't want to exceed that 5cm while applying a solution.

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ntyperteasy t1_j1mbhwh wrote

It is not a bad idea. It is done with special acoustic glue - it is very gooey and doesn't dry hard like most glues. Good damping. They suggestion you apply it in a random pattern and not stripes or dabs to avoid creating sharp resonances.

I don't know if you can get it where you are, but perhaps once you see it you can find something similar or at least read the instructions to get some tips... And, BTW, they still want some screws for mechanical strength and to satisfy the building codes.

https://www.greengluecompany.com/

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Snoo_9017 OP t1_j1mep3n wrote

Haha, I also added an update to my post, the guy tests carpet glue 3 4x cheaper than green glue but performs better.

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lindenb t1_j1muj62 wrote

Having built a number of professional sound studios I can confirm that the approach is valid. It won't do a lot for high frequency sound transmission but is very effective for low frequency. Typically 5/8 drywall layers (2-3 depending on the STC requirement) applied with acoustic adhesive with each layer staggered horizontal vs. vertical . This is one product but there are others from which to choose. https://www.amazon.com/Case-Green-Glue-Noiseproofing-Compound/dp/B000SKWD8Y?th=1

Building double walls with sound damping bats in between is also another approach but typically is less effective at low frequency- given less mass. Unless you are trying to emulate studio conditions I'd stick with layering drywall but be advised that at 3 layers you will be adding a lot of weight on the studs and flooring so unless you are building on slab you may want to give consideration to achieving a reasonable balance between STC and weight/as well as cost.

As for high frequency remember that any penetration of a space--for piping, hvac, electric outlets as well as doors and windows is a potential source of kleaking high frequency noise into and out of a space. All penetrations should be sealed with a firestop rated acoustic sealant. Solid core doors and fixed windows--if possible with acoustic caulking and multipanes. Now, none of this addresses sound shaping and the elimination of standing waves etc. but if the purpose is to create a quiet room--and/or shield adjacent structure from noise it will give you a decent result. Good luck.

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SegmentalMutter t1_j1lwg3d wrote

Lots of small dabs and 15mm sound block board?

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Snoo_9017 OP t1_j1me6vp wrote

do you mean 15mm sound block board sticked to the drywall and then dabbed with small punches?

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Killawife t1_j1lx6yi wrote

Theres a special type of plaster for just this job. Check out the video: https://youtu.be/K7ODiCQhS-o?t=115

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Snoo_9017 OP t1_j1meh4y wrote

this is an interesting one, Ardex S48 is a tile adhesive, wasn't aware tile adhesive would work as well. Thanks for the suggestion, If I can get rid of 20 bags of plaster adhesive then I may apply this, wouldn't drywall adhesive work in the same manner as well?

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Killawife t1_j1mxa0y wrote

Well As you might have noticed from the video I'm not from the US so plaster adhesive really doesnt say anything to me. But there exist a product that is used for putting drywall on concrete walls. In sweden its called gipsputs but I don't know what its called in the US, maybe plaster adhesive? Its sounds about right. The method for using it just clotting on the wall in big patches and then pressing the drywall to the wall.

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jewishforthejokes t1_j1o0dpx wrote

One reason you dot and dab is so it can squish out and expand as you push the wallboard into place. If you did it like tile, made it really flat first then added grooves, you could get away with it, but it'd be a lot of work.

Unless you have tons of free time, I'd sell the 370 eur of stuff for whatever you get and buy the carpet glue. It won't be worth the aggravation to make do.

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