Duplex sound dampening party wall

[jabjab]

I'm getting various drywall companies suggesting different things so I'm getting in a rabbit hole about how to do this right.

One person suggested roxal insulation with soundbar and 5/8 drywall and another person said roxal doesn't provide any more sound resistance than owens quiet zone insulation.

Another company said to see 2 5/8s with "green glue" on each side of the wall (essentially 4 layers between me and the other side.

Anyone have known proven ideas? Also looking for ideas for the ceiling cause it has a legal basement suite.

[Ca_Silvia13]

I briefly lived in a side by side home, new build. And the builder used 2x6 walls on either side of 2" air gap, 2 - 5/8 boards on either side as well. No fancy insulation or sound board built into the wall.

It did not 100% stop the noise transmission through the wall. I see you are using 2x4 so i don't think you will see any real benefit from over thinking this.

[Tik-Tok]

Poured cement.

[suntan]

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Poured cement.

Concrete.

[tha_bandit]

the typical setup is:
5/8" gypsum boards (type x)
2x4” wood studs spaced 16” OC
1 layer of 3” Safe’n’Sound® Wood Stud
Resilient Channels spaced 16” OC

this gives you a STC of 45 which i think for legal suites is 42?

[firebane]

A lot of people are recommending this stuff https://www.homedepot.ca/product/son...ick/1000441119 over top of drywall.

[nissanK]

Another consideration (sorry to add to the rabbit hole) is HVAC ducts and vents.

Sound is like water, if there's a hole somewhere, it'll find it.

That being said, each cumulative layer of sound diffusion, mass and air gaps all work together to mitigate sound propagation. You want the highest cumulative STC (Sound Transmission Control) rating. So for your example, ideally you'd want and STC rating of 50 and higher.

https://en.wikipedia.org/wiki/Sound_transmission_class

[lamp_shade_2000]

I built a home theatre with a friend last year. After a ton of research we went with safe n sound in the walls, then a layer of green sonopan, then resilient channel, then 2 layers of 5/8 drywall with that acoustic seal green glue stuff in between. The reduction in sound is massive. It wasn't cheap though and it was a ton of work.

[suntan]

That's an impressive 7 inches.

[jabjab]

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I briefly lived in a side by side home, new build. And the builder used 2x6 walls on either side of 2" air gap, 2 - 5/8 boards on either side as well. No fancy insulation or sound board built into the wall.

It did not 100% stop the noise transmission through the wall. I see you are using 2x4 so i don't think you will see any real benefit from over thinking this.

I realize it's impossible to stop all noise, even with a concrete party wall. What kind of nosies did you notice come through?

[jabjab]

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I built a home theatre with a friend last year. After a ton of research we went with safe n sound in the walls, then a layer of green sonopan, then resilient channel, then 2 layers of 5/8 drywall with that acoustic seal green glue stuff in between. The reduction in sound is massive. It wasn't cheap though and it was a ton of work.

I really like this. I think using one layer sonopan pan and then one 5/8 will be enough since my set up is off center studs and the drywall won't be attached to their unit

[Ca_Silvia13]

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I realize it's impossible to stop all noise, even with a concrete party wall. What kind of nosies did you notice come through?

Raised voices/yelling and you could hear when the neighbour walked up and down the stairs.

[pf0sh0]

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Concrete.

Our party wall is ICF and we hear nothing

[ercchry]

Lived in a concrete party wall duplex once… could always hear their phone ring… concrete condo, always hear a yappy pocket dog a floor up. Seems to be the high frequency crap that cuts through

[jabjab]

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Raised voices/yelling and you could hear when the neighbour walked up and down the stairs.

Luckly our stairs are on the opposite sides. I'm ok with hearing low frequency sounds but don't want the higher frequency stuff like yelling and sex sounds.

I think sound insulation may have helped it a bit in your set up.

[eblend]

I heard that open cell spray foam is also very good for sound deadening. Do your research, but perhaps you can drywall the one side, and then spray foam the entire cavity and drywall the other, and be good. I don't know the cost, but the fact that it will get into every nook is pretty appealing. Sorry I'm a big spray foam guy, love that stuff. When I did my basement long time ago as a theater, I researched the hell out of this as well and realized it can get very expensive very quick, so in my case all I did was resilient channel, but in ideal world it would have been that + two drywalls with that green glue, and some batts in the cavity.

[jabjab]

What we decided to do is double 5/8 drywall with green glue in between with Owens corner quiet zone batt insulation for the party wall.

Basement will be resilant channel with the quiet zone batt and 5/8 drywall. Hoping for best.

[88CRX]

What does your realtor suggest?

Also all this shit is set by the Building Code... so your builder/architect/realtor should be telling you what to do, not the other way around.

[RawB8figure]

Who's building this?

[jabjab]

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Who's building this?

This is a JV with a friend who is taking the other side. He is a smaller builder in Calgary but doesn't do too many attached homes. He says code is fine in the units he has done but I want a little extra.