Remove plaster for soundproof?
The quotes I received were for one wall about 9’h x 12’w. This is the party wall in a townhouse and the room is our primary bedroom.
JoeBushwick
in General Discussion 3 years and 9 months ago
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28 replies
colonialrevival | 4 years ago
I’ve got a brick party wall with plaster applied directly to it, and it’s a sieve for noise. It is likely to have missing bricks from past intrusions, old gas lamp lines, etc. I’d like to remove all the plaster, fix the brick underneath it by replacing missing bricks and repointing, insulate the joist pockets with rockwool, and then cover back up with mass loaded vinyl, rockwool over that, and a quietrock wall in front.
The only problem, none of the soundproofing guys I’ve talked to are interested in the remedial work and only want to do the easy job of adding new material. I couldn’t bear the thought of investing money into this wall without fixing the source problem. Who should I call to get this done?
hkapstein | 4 years ago
If you’re going to build a new wall in front of the old wall, you may was well just just leave the plaster and invest your efforts in decoupling and adding layers. The party wall is quite thick anyway, and parts of it are controlled by the neighbors and you won’t be able to do anything about the defects on their side, and it’s unlikely that this will make a big difference anyway. The plaster removal and masonry work will be a messy, costly, and difficult job, and you likely won’t find the smoking gun you’re looking for, and you’ll wish you hadn’t done it IMHO.
colonialrevival | 4 years ago
Thanks Urbandad.
FWIW, our party wall is only 2 brick wythes thick.
Curious about the joist pockets, though, as the sound does also come through the floor. Basically, I’m incredibly nervous about investing time/energy/$$$ most of all into something that will still have potential pitfalls or variables left unchecked. Should I have my soundproof guys pull the floor/subfloor up and throw some insulation there? Can’t do it from below as there is decorative moulding.
colonialrevival | 4 years ago
After sitting with it, I’m not sure I concur with your analysis — we can clearly hear the words to every conversation between our neighbors. Are you certain that stripping plaster and repointing is a waste of time?
Guest User | 4 years ago
No disrespect to those who clearly know more. If it were up to me I would do exactly what you you want to do. I agree with urbandad that it is more costly, difficult and messy. 9/10 people you call will tell you to do it the faster way. They probably don’t want you to waste your money and live through this. In my experience people would want it done the faster way because the alternative will be more expensive. Talk to a few more people then decide. Good luck!
JohnHancock | 4 years ago
Perhaps the neighbors have the plaster removed, in general I think the plaster is a decent solid layer. I would build upon that. Sound is vibrations so to stop sound traveling you have to “float” things like in a recording studio where you separate layers.
This is not really possible in a residential space but we do the best we can.
Guest User | 4 years ago
Definitely need to isolate the vibrations. In gut construction we have staggered two insulated walls on neoprene separators, not unlike mounting HVAC on a concrete pad. The plaster in itself is a good sound insulator.
Sound is tricky. I once lived in a 1920s building with gypsum plaster walls. The only places where you could hear the neighbors was where they had done a hot water riser replacement – I could hear the couple next door arguing in their kitchen if I opened our tiny pantry and inexplicable the interminable playing of The Girl from Ipanema was only noticeable under water in the tub!
Guest User | 4 years ago
It depends on what’s behind the plaster. I have plaster on brick and can hear the neighbors in areas. In other areas it appears my walls are built out. If the plaster is directly on the brick, then it may not be worth it to go on an expedition. Easier to add like Urbandad and JH are suggesting. As mentioned above, plaster itself is a good insulator. Can you open an area and see what’s behind or did you do that already?
colonialrevival | 4 years ago
I appreciate all of your thoughtful comments. They’ve helped remind me that I should add — the neighbors have intact plaster on the same wall. The wall is plaster applied directly to brick. There has been chasing into it on both sides for power outlets, etc, over a number of years I’m sure. There were once gas lamps in the room and those lines are no longer in use, but I’m certain there’s a gas pipe behind. There are large sections of the wall that I can knock on and the wall sounds hollow, but nothing predictable that would indicate a wooden partition to close up a past passageway or something.
As the brick is only 2 wythes thick, I’m guessing our joist pockets go all the way through and sound can travel that way. While I hear you all on not going exploring in the plaster, would it be beneficial, still, to pull back some floorboards and insulate there? Moreso than just pulling off the baseboard and spraying expanding foam beneath?
Guest User | 4 years ago
I called Soundproof cow and the guys there were knowledgeable. They didn’t try to sell me on anything – worth a call to ask. Sounds will travel up along the side walls but are you hearing those sounds from different floors or is it form the adjacent neighboring floor?
colonialrevival | 4 years ago
Just from the adjacent floor primarily, though we do get occasional sound travel when they are loud downstairs.
andriywww1990 | 4 years ago
i once did what jane did and called an accoustical engineer located on St Marks in the city. and like what jane says, the guy spent a lot of time explaining all this and did not try to sell me anything. i wish i could find his name, i would post it here. he told me that most sound travels along the wood joists and into the pockets and into the wood in the neighboring apt, which is why you are hearing it when they are down below, it passes their cieling into your floor, i suppose.
the guy i called at all sorts of solutions and more involved isolating floors and ceilings with all sorts of materials i know nothing about. the walls were less of a concern.
colonialrevival | 3 years and 11 months ago
Just getting back to this. I’ve received from pricy quotes from some soundproofing experts, many of which involve layering mass loaded vinyl over the plaster, furring out a new wall, filling it with rockwool, and layering sheetrock and mass loaded vinyl over it. This sounds like a great way to isolate the wall, and I’m just about ready to go for it.
However, I’ve read lots on here and elsewhere bout how sound also travels through party walls between joist pockets. I’ve _really_ done my due diligence with Googling, however a joist pocket here differs from a joist pocket in the majority of other fully detached American suburban homes. Should I be opening up the floorboards and ceiling before building this wall? If I were to do so, what’s the best approach to slow sound transmission in these areas? My initial inclination would be some form of insulating spray foam, followed by a thick and heavy insulation (probably more rockwool).
I’d be curious to hear from some of the contractors on here (UrbanDad, RestorationContractor come to mind) what their approach to this is — I d on’t want to go on a wild goose chase, but it’d be great to fall asleep at night without listening to my rambling neighbor’s phone conversations.
andriywww1990 | 3 years and 11 months ago
“green glue”. it is a semi solid caulk that could be laid down on say the joists and the sub floor would be put on that or perhaps the green glue is laid over the old sub floor and a new subfloor over that and the glue isolates the wood, breaking transmission. i just googled green glue and they have a website. check it out. (keep up the research; pretty soon you will know more than urbandad and i am surprised he never mentioned it here; i did not mention it in my post above because i have never used it and it sounded “gimicky”).
perhaps someone on here has used Green Glue. i seem to recall someone mentioning it here years ago, like over a decade. or did the accoustical engineer i spoke to mention it?
(restoration contractor is a full on contractor and has probably done this, urbandad is not a contractor but is good at internet research and regurgitating what he finds on here without admitting he has never done a lot of what he talks about himself or giving credit to where he read it; it sounds like urbandad has “properties” and that means he has not been spending loads of money and time trying to isolate sound in coops and condos).
colonialrevival | 3 years and 11 months ago
Green glue doesn’t seem to be highly regarded among professionals I’ve spoken to when compared to something like mass loaded vinyl. A source I found (in the UK) recommends filling any gaps in the party wall joist pockets with a dense spray insulation, and then peeling back a few floorboards, and filling the gaps between each joist with 5lb/ft^3 dense rockwool based insulation. Will continue research, finding more luck with UK sites since their housing stock compares nicely to ours.
Guest User | 3 years and 11 months ago
Have you called https://www.brooklyninsulation.com. I’m not sure if everyone we think is a contractor is a contractor on this forum. Some are just knowledgeable but may not know specialized things such as this. It isn’t a common renovation ask though it should be.
andriywww1990 | 3 years and 11 months ago
jane, even if some people are not contractors, it would be ok if when they commented that they would admit that they “heard it somewhere” or “read it on the ‘net”. especially here with something so specialized as this that few of us (not me) have done. if urbandad were here he would research the answers (anyone of us can do that) and spit it all out on here without admitting he has never done it (there are ways some of us can see through what he is doing, certain language and the “breadth” of the knowledge; unless you do something everyday, you begin forgetting things even if you did them everyday twenty years ago). its sort of a slap in the face to people who work and have had to learn over time by doing.
op, it sounds like you have to call someone who is engineering this stuff here in the city, because of the joist pocket issue in the old attached houses. the link jane provided.
i recall enough of what the engineer i spoke to said about how to d o this to see if i can run this down on the ‘net and post a link here. i recall “what” he said had to be done, but do not recall “how” he said it is done. if i find a link pertinent to city houses, i will post.
andriywww1990 | 3 years and 11 months ago
colonial, in truth, i really don’t want to learn anything new about interior construction and not anything about sound transfer. its too scientific for me. But since no one else is posting anything today, i just googled “floor joist sound isolation” and returned something from the “soundproofcow” that someone mentioned above. they are “floor joist isolators” that look like the cap over the top of the joist and from there someone sets the sub floor. the guy i spoke to years ago said there was a way to isolate the floor. and ceiling.
if you have already found this stuff i am posting but were not sure of the application, ask. some of us (me included) know enough about elementary wall construction that we would know how and where these things might go.
i am going to go back down stairs and will keep reading. i am sorry, it will come in multiple posts.
andriywww1990 | 3 years and 11 months ago
so i also googled this term: “joist hangers to isolate sound” and if i googled it again i would use ” isolate or stop sound transfer”. this just returned all sorts of results offering up all sorts of brackets from several companies.
if i were doing this in my house, i would not be calling anyone in. i would be reading and reading and might talk to someone along the way and would read more. it helps to have a basic understanding of wall and floor and ceiling construction, but that is easy. you can research this just as good as anyone else on here can.
some of these things these people advertise may be very similar and the choice may come down to one thing: cost.