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Soundproofing with exposed ceiling

Member for

1 month 4 weeks

So I've seen a lot of studio spaces and researched a lot. Basically I'm remodelling an 35' x 25' unfinished room (looks like an unfinished basement but above ground) and building 3 rehearsal rooms.

Soundproofing with exposed ceiling

2 things I'm trying to determine. I'm doing R-13 insulation and double 5/8" sheet-rock with green glue on all walls. Should I also run hat channel and isolation clips before the sheet rock? And if so I don't believe I need to do this on the 2 exterior walls just the adjoining room walls correct? How much difference will the sound clips really make with this set up?

Also dumb question but the ceiling is exposed, the roof is the only thing above that but if the rock was run all the way to the ceiling, leaving the exposed ceiling would still have substantial bleed to the next room wouldn't it?  Asking because it will be a task to frame around electrical to be able to double rock and green glue the ceiling but it may be the best choice I believe? 

Any thoughts/input would be appreciated.

Soundproofing with exposed ceiling

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Member for

7 years 7 months

paulears Mon, 07/26/2021 - 13:40

Two layers each side is pretty good, but I'm a very great unbeliever in green glue because of the mess I got into on my umpteenth studio build but the first with the stuff. I'm positive that the claims are possibly accurate, but for me - the extra claimed isolation would have been easier and cheaper with another layer on the walls and ceiling. You've already done the studwork with a single dividing partition, so the snag is that both rooms share a very thick barrier in the walls. If you thump the wall, it would transmit through the solid clips and hat channel and through to the other side. I'd certainly be thinking about the isolation clips because you need to decouple the walls. I'd have had two sets of studwork and air space between, then fixed the sheet material directly to the timber. My view is that hat channel is great for offices, but if you use timber, there's little point in hat channel and sound clips and the budget is really hit. Timber is also forgiving and nice to deal with. Metal is not!

The snag seems to be the ceiling. are you intending on haning the heavy sheets directly to the joists above? Wo;;they take it, and importantly will you hear rain and birds if that's an outside surface above? Most of your decisions have been made it seems. I'd be concerned about how to isolate the heavy ceiling from a fairly lightweight structure above. Have you sufficient height to stick 2x8 joists across from the studwork to carry the ceiling load and leave a gap above?

Member for

12 years 2 months

kmetal Mon, 07/26/2021 - 13:51

Hi, welcome to RO!

I will start by answering the questions you asked, then add some stuff I think will help.

Risc1 clips- you only need to decouple once. So if each room has its own 4 walls (and ceiling) then you do not need the clips, it it will actually make things worse.

If your room is sharing walls, then you need to use the clips on all walls, not just the shared walls, since the shared wall connects to all the other walls.

Risc1 clips give about 9db-12db of additional isolation of airborne sound, ie music. They have a weight limit of 2 or 3 layers of drywall. For more than that you need a heavy duty clip.

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Ceiling- yes that common ceiling is known as a "flanking path". Sound will bypass the walls and travel directly thru the ceiling from room to room.

You can either build an independently framed ceiling, that rests on the rooms own 4 walls, or you can use Risc1 clips on the ceiling for a similar effect bur with less isolation.

Your isolation is only as good as the weakest part of the assembly, so you want all the surface areas to perform equally.

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Which assembly you choose depends on how much isolation you actually need. Are they band rehearsal rooms, cello, vocals???

You need to define how loud the source is, and how quite it needs to be outside the room.

Example- drums are 115db, the living room above should hear no more than 55db. You need a wall/ceiling assembly capable of 60db sound reduction (TL - Transmission Loss).

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Green Glue- note green glue is most effective at vocal ranges 80hz-20khz, but music is full range 20hz-20khz.  If isolating just vocals, GG is a viable option. But for bands, drums, bass, your better off with the equivalent drywall instead, since it will isolate those low frequencies.

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I highly suggest you buy Rod Gervais's book, "build it like the pro's" as it is a great guide for what you're trying to do. Its full of drawings and plans.

If the framing in your photos is your studio, there are some very important problems.

The footers/sill plates should be pressure treated because they are.in direct contact with cement.

That frame underneath one of the walls looks highly suspect, and should not be there. The studs should run from footer to header. Use double or triple footers if you need to raise the frame. You want the footer to run the full length of the wall.

The walls are touching the existing ceiling making the walls pretty much ineffective for isolation.

The electrical is using flush mount boxes, which will blow your isolation. They should be surface mount boxes, with a sealed penetration for the wire.

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You will probably find using standard materials, wood/drywall both the cheapest way to go, and most effective. Resort to GG and Risc1 clips only for specialized situations..

The book will address adding drywall to the existing ceiling in the bays, doors, windows, HVAC, HVAC, HVAC, clean electrical, and the studio construction needs. Did i mention HVAC? Lol. That's a big concern.

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Anyway hope this helps, feel free to ask many questions, planning is critcal in studio construction.

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1 month 4 weeks

iremain333 Mon, 07/26/2021 - 15:42

This is all great info and greatly appreciated. The rooms will most likely be rehearsals for loud rock bands and since they share walls I should go with hat channel and iso clips yes?

My plan now is to frame our the ceiling and run joists across from the studwork leave a gap...is 1 inch sufficient? There is no upper level and above that is the outside roof.

And would you suggest a 3rd layer of 5/8" drywall instead of GG?

Surface mount boxes makes sense. I was going to use SpecSeal SSP Putty Pads on these flush mounts....bad idea?

Ahhh yes, the AC. I will put mini splits on the back wall of each room. 

I definitely will get Rod Gervais's book. I have a big building and hope to continue building more rooms in the near future, however for these 3, this is the framing I have to work with so want to do the best I possibly can.

Member for

12 years 2 months

kmetal Mon, 07/26/2021 - 19:07

Its cheaper by quite a bit to just build the 4th isolated wall, than to put clips/ channel on all the walls, in every room. Your one or two walls away from as good as it gets as far as isolation construction. ie decoupled walls.

The downside to clips is their not as good at low frequncies as a double wall, and they have much less load bearing capacity. So if you decide after testing you need additional layers of drywall, with the clips you can't do it. And their cost, and you have to be dilligent with the install, since they have no tolerance for error there.

Basically use clips only where you really need them, otherwise use standard framing. 

By the time you install all those clips and channel, you could have redone those frames properly, and built out another three rooms. And spent less.

With clips you also need to plan out exactly where any lights and ducts will be, and make sure they don't eat up your load limit, while also making sure you maintain isolation and have proper fastening (ie extra nailers in those areas). You would have to re mount all the electrical boxes too, since they would no longer be flush when the clips and channel were added.

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If using clips then you may as well use green glue and max out the drywall layers. This is because your severely limited with the load bearing, and can't add green glue later.

Otherwise framing and the 3rd and probably 4th layer of drywall. 

That's really the best way to go. Otherwise your spending extra money for a more limited assembly, that won't perform as well.

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Mini split units require fresh air exchange from outside the building, so you will need an HRV/ERV unit and some ducting to exchange air to and from the room.

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If you can find test data on the putty pads that show they can keep up with an 2-4 layers of drywall, then use them. Otherwise just use surface mount boxes. They are easier to expand, and give you the best isolation possible. And its cheaper most likely.

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You want to avoid "specialty" acoustic branded products as much as possible, sticking with standard building materials. Those products should be reserved for instances when there are no other options, and that justifies the price and compromise in performance

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1" clearance between existing and new ceiling joists is fine. Each room needs its own set of joists, sitting on its own walls.

Member for

1 month 4 weeks

iremain333 Tue, 07/27/2021 - 04:55

Framing a 4th wall in one of the rooms may be an option. Unfortunately framing a 4th wall in the other is not due to the door frames being too close on each side. Now I'm down to figuring the most effective soundproofing I can possibly do with a single framed shared wall. I'm not as concerned with the noise level outside of the rooms, but I am on the noise from inside room to room. 

I am going to see about changing the flush mount boxes to  surface mount on the shared walls but will look into putty pads more as well since I already have flush mounts in place.

Bottom line these will be rock band rehearsal spaces and I've been in some bad/loud ones, but I want these to be as soundproofed as possible with what I have to work with.

Member for

7 years 7 months

paulears Tue, 07/27/2021 - 05:25

No idea where the text went?

 

The book is actually very useful. The weight of drywall got me on a project years back. The studwork was on neoprene, and having raised the bottom plate by the 6mm I made sure the plasterboard (sheetrock) was all off the ground, with the weight taken by the clips. My intention was to to install some MDF ducts at the bottom. I measured very carefully and installed the wall materials. - two layers of 12mm plasterboard and one 18mm layer of MDF. I had not done the calculations properly - and the weight of the three layers dropped the walls enough that the MDF duct did not fit - maybe 4mm? A gap opened up at the top.Clips add around 25mm minimum and the weight is cantelivered out from the vertical support. The weight of the wall ended up directly coupled to the floor - which luckily was concrete but all the effort in the metalwork was pretty well wiped out. Since then, it's been double studs with a gap, and sheet directly attached.Most of my progress has been built on sorting issues from a previous one. kmetal mention the sealing. Extra layers and the other popular isolation systems get wrecked when you punch holes through for air handling, cables and plain gaps! My systems are a bit odd in the design, mainly because my spaces have always been space precious, so boxy room sounds the enemy. Sheet material here in the UK is a stupid mix of metric and imperial. Plasterboard comes in 1.2 x 2.4 sheets, 12 or 18mm thick. Plywood and MDF is 1220 x 2440 9/12/18 or 25mm thick (the old 8x4ft size) I evolved the hybrid platerboard and MDF approach because MDF is very dense, and solid - but on the inside is tough when people bash into it with cases . It doesn't damage like plaster based panels. So I build where I can in 8x8, or 8x4 studpanels, and then I toe them in or out to prevent parallel surfaces. Corners might be 85 or 95 degrees. Maybe even further away from 90 sometimes. This really makes a noticeable difference - that 'boxeyness' largely gone! However - there is a downside. 90 degree corners mean ceiling sheets fit, but odd angles makes filling gaps damn hard. My solution is quite novel. I sit the MDF panel on top of the top plates of the studwork. The angles don't matter - the top is sealed. You can screw up through the top plate for fixing. Then you add the joists on top! The plasterboard then can come up from underneath and small gaps don't matter. My last project had a pitched roof above the studio which we had access to, and the owner wanted green glue. I failed to put him off. I had an idea to cut the plasterboard into strips - joist width apart, and use these panels for accurate joist spacing. So once the MDF was up, we sat in the roof space. squirted the dreaded gunky stuff and sat the plasterboard on top, then another layer - then pushed the joist up to it with green glue on the edges too - and used clamps to squeeze it tight. The we screwed up from under to secure the joist to the plasterboard. then the next strip and so on. It was also really simple to make sure the plasterboard joints were staggered. Probably the best ceiling sealing I have ever done. How much the puncturing of this with the air handling silencers and tubing hurt it, I don't know. For fun, we played pink noise in the building pre-build and marked where the speaker went, what gain settings were used on the playback system and the recorder and mic placed outside- but it didn't produce a meaningful result - our SPL level was not high enough, despite being loud because at the end, after the build we couldn't detect it. Not remotely saying it was total isolation, but our test conditions were flawed.

All I can say is that a room within a room, no shared studwork between two areas and attention to the ceiling really seemed to be the best isolation I've had with my builds so far. With amazingly loud audio inside, there is just perceptable after midnight, a very low kick drum 'duh' sound that we can't localise. He's very happy.

The other comment re using metal and tophats is that you need to be very careful with fixings. The special screws come in many lengths. Think how easy it would be to mis-measure and stick a screw into the wooden joist if you measured wrong, ruining the isolation and you'd never find it.

There's some really useful stuff on windows in those books - they're not as bad news to isolation as you think. I've even got cheats for doors with door closers. Using mics and headphones to listen for leaks - doors were always a compromise. Proper acoustic doors with squeezing seals are out of my price range - so it's heavy fire doors on inner and outer structures, with strong door closers. My woodworking and hinge alignment was often the cause of little leaking gaps. My construction skills are firmly DIY. So I fit the door, and the door closer, then I get the door closing timber, with the foam edge fitted, and push that against the door when its in the closed position - then secure it. Do this on all four sides and you have a perfect seal. trying to hang a door to prefitted stops never worked - alignment was always off. Doing it backwards was so much easier. You won't find general builder who remotely understand any of this. They never have to work to these rules - just decorative fixes. another tip is to look at your wall layers and when cables come through stagger them. Put cables through from layer one. This is awkward but worth doing, even if it gets in the way. So the hole on the first layer is offset. When you cover it with the next layermake the hole there maybe 30-40mm away, and bend the cable at right angles and link it with a slot in the panel. The final layer covers the slot. You need three layers to do this, or filler on two, which tends to pop out! With three layers there's no audio path. It does mean you need to put your cabling in early - but if you have planned well, this works fine.

Kmetal also mentioned the danger of putting plaster based sheet materials on the floor directly. I did this on one of my studios and its amazing how soft and discoloured it gets after just a few years - you really have to break the moisture travel with a barrier. I suspect its the hotter moist air inside and in winter the colder temperature of the concrete and it's not just travel, but condensation evaporating out on the colder surfaces.

 

I'm not remotely an expert on these things - for me it's the books for detail and specifications and then common sense and a degree of trial an error. Every one gets better. I wanted to trying soffit mounting the monitors on the last one - and my friend's  chosen monitors had a soffit mount setting. We set up a chair and measured angles very carefully. The room was normal construction, so the angled in and angled down panels were built as a separate stud. Making those panels stretched my maths and cutting to the extreme - the results were really nice in a compact space.

Member for

1 month 4 weeks

iremain333 Tue, 07/27/2021 - 10:57

Thanks paulears and kmetal for being super thorough and super helpful with all of this. The studio space pictured looks great! That being said, I'm looking into adding a new 4th wall on one room where I can. Still trying to figure the best way to frame and isolate a ceiling in each room...there are 2 long 2x8 joists that run the width of the building through all 3 rooms so I can't 100% isolate but researching the next best option.

On the other 2 rooms that share the single wall is my best option to insulate and triple layer each side with 5/8" sheetrock and then add corner baffles, acoustic panels etc inside the room until its good enough for band rehearsals?

Seems to be my best option.

 

Member for

7 years 7 months

paulears Tue, 07/27/2021 - 12:27

Are you doing the work yourself/with friends etc or using a builder.

There's that law of diminishing returns to consider. Every layer of sheetrock you add to the walls improves performance - but it's the whole thing that really matters. If the weak link is the ceiling, rather than the walls - the extra work should be directed there - to where it makes the most difference. If your walls only let you hear the bass or kick drum, that might be liveable with but if the bass leaks up and over, finding the weak links - that needs sorting. It could be good to put in just a couple of layers and then make some noise, and hunt around with headphones and a live mic and find the place it's coming from - then spending time and money on that. When you self-build, you get surprises - sometimes good ones. The professionals can predict these and its's sorted in the plans. None of mine EVER follow the plans because you find problems to solve you didn't notice and have really good ideas sometimes during the build so you can change course.

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1 month 4 weeks

iremain333 Tue, 07/27/2021 - 14:17

I have a framer I'm working with, he does solid work he's just not familiar with soundproofing so I research and figure out problems as we go so to speak.

And where we are now is moving some old electrical in the ceiling and attaching sheets directly to the joists above and adding a couple new ones to be sure they will hold. So no they will not be isolated rooms but at least they will be sealed.

Have you ever used acoustic caulk to seal anything? Like where the sheetrock wall meets the ceiling?

Member for

12 years 2 months

kmetal Tue, 07/27/2021 - 17:24

It’s easy enough to just move the door opening over so you can add that 4th wall in the other room.  A room with adjoining walls has no chance at soundproofing a band, even moderately. Think about how easy it is to hear thru walls in a regular house, now imagine that only 6db quieter, that’s what your proposed plan will get you.

you absolutely need to decouple. A wall is easier than clips but you need one or the other.

for the ceiling you can use one of the suspended ceiling designs in Rod’s book.

your framer is doing non standard stuff that I’d be surprised is even safe. I’m not sure they know what they are doing, I suggest you get someone else. That elevated frame is not good structurally, and their wasting materials with double footers, plus they are not pressure treated, so will  be prone to rot and mold.

if you want this to work you have to do it right. It’s not difficult, just specific.  I’m telling you that what you have will be no better than a regular room in a house as far as soundproofing, and won’t put a dent in the band volume. You may as well just make it one bigger room and the other decoupled room.

use butyl or 100% silicone non hardening caulking, or Big Stretch brand caulking. Acoustic caulking is expensive and no better than the above.

im not trying to be mean, just honest an truthful. These are not opinions they’re facts based on test data and proven math. Hopefully this will save you money and aggravation.

Soundproofing is a situation where small mistakes can ruin the entire thing. 
 

take your time and plan it right.

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1 month 4 weeks

iremain333 Tue, 07/27/2021 - 19:19

I totally get it man. If I move this door frame and build a 4th wall frame 2” from the other wall then I will have 3 rooms each with 4 decoupled walls. The building is old and has alot of obstructions in the ceiling. In order to completely isolate it and frame the ceiling to sit on top of the walls my ceiling height will just be too low. So it will have to touch shared joists and shared studs, possibly going straight to the existing exposed ceiling. Is that going to kill my work done decoupling the walls or will it still make a huge difference/improvement?

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7 years 7 months

paulears Wed, 07/28/2021 - 08:42

Frankly, yes - it's going to kill it. The usual trick where you have drop joists, is to build around them. If the joist comes down to get in the way - you need to look at the sheet material - lets say two layers of ⅝ which means 1 and a ¼" inches. Let's then take a gap of say ½" - that means you measure the height of the joist that is in the way, and then lower that measurement by 1 and ¾" see if that is walk undesirable. If it is, you then put in the wall supported trusses either side of the obstacle and box it in. So for me its just a case of seeing if maybe two inches lower that your joists is acceptable and safe. If it is - just box it in, and maybe use the drop to create some angles, or build in some absorption if you need it - or the aircon, or ...........

Member for

12 years 2 months

kmetal Wed, 07/28/2021 - 13:49

If attaching walls to a shared ceiling, you connect the walls to the ceiling with risc1 clips and channel. So the walls are no longer connected by a hard connection. (Aka they remain decoupled)

Then you hang the drywall for each rooms ceiling with one of the decoupling methods described in rods book. Like risc1 clips, a suspended ceiling ect.

You can also remove the obstructions, or if possible run the joists so the obstructions fall in between the joists.

Its difficult to give specfic advice without a better description or drawing or photos of the existing room.

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1 month 4 weeks

iremain333 Thu, 07/29/2021 - 05:10

I appreciate you guys taking the time to help me with this. I currently am going to backtrack a bit and move the one door frame over a few inches to make room to build that 4th wall so I can do that in both rooms. Also I remeasured and if I come 2" below the obstructing joists I could frame the ceiling that would be 91-92" high. A bit lower than I'd like but then I would have 4 decoupled walls and ceiling. Could I get away with a single layer of drywall on the ceiling? If Im not as concerned with sound going up and out but rather from side to side...room to room?

I do have Rod's book on the way tomorrow so that will be my weekend homework 😎

Member for

12 years 2 months

kmetal Thu, 07/29/2021 - 12:33

Congrats on Rods book purchase, it lived with me on studio builds for years, and i still frequently reference it.

Sound does not distinguish between up and down, it simply travels the path of least resistance. So each surface must have the same mass.

Also we didn't discuss the floor. Is it a slab on grade (the ground).? If so your all set.

As long as you have 1" min. Clearence between the ceiling joists and obstructions your good.

 

If they stick into the joist bays, thats fine as long as the joists and drywall have 1" clearance.

The book shows this in the ceiling section.

Member for

12 years 2 months

kmetal Thu, 07/29/2021 - 19:47

I just realized the photos are upside down. So while the framing still needs to be decoupled from the existing ceiling, its not as ridiculous as i thought it was originally.

If you run the ceiling joists parallel with the beams, you should be able to tuck the beams in between the joists, giving you the highest ceiling height you can achieve there with a joist framed ceiling for each booth. This would be simple if the new joists end up a little wider than the beam. If not you could build "chase frames" to box out the beam, leaving more height every where else.

You could also *possibly* attach the drywall to the existing framing in the ceiling via risc1 clips and just "box out" the beams. This assumes the existing ceiling can carry the new weight

Two of my builds were in an old mill, and i just framed the booths so that the new independent ceiling outlined the beam with 1" clearance. It looks similar to your existing conditions.

Both are covered in the book. The book shows a basement, but the principles are the same in your room.

Sorry for the oversight.

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1 month 4 weeks

iremain333 Fri, 07/30/2021 - 04:39

Ha! Ok, that makes me feel much better. I could not figure out a couple things you were saying about the framing but turned it upside down and I see how insane that looks 😂. Now I can sleep a little better. Strange the pictures are upside down for you, they are shown correctly on my end. 
 

And yes, I’m working with a concrete slab floor so great to hear you say that. 
 

Waiting on the book until I make any executive decisions but what I plan on doing now is instead of building that 4th wall in 2 of the rooms I may build 2 walls inside the middle room with a framed ceiling, basically a room inside the room. I’ll sacrifice a few inches on each side snd in height but that will completely isolate the middle room then look at attaching the ceiling to the outside rooms directly to existing ceiling to get a little more height. 
The center room will just be the smaller room and the others stay the same size.

Looking forward I getting the book today. Still need to be sure the doors are properly sealed, sealing around light fixtures, and other things I’m sure I haven’t thought of yet. 
 

What part of the country do you live in? Whenever I get back on your I owes y’all a nice dinner 🤣 

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