Hello
I've been reading this forum for a while. Great resource, loads of info, so thanks for hosting John!
I have a builder coming on Thurs 30th Mar (this week) to start my build but I've come across a couple of things I'm confused about.
I'm converting a room in a ground floor / basement (built on a hill) victorian terrace, in Bristol UK.
The room is approx, 4.7m x 3.2m x H 2.15m. My main concerns are the ceiling, and the two walls that go onto neighbours either side.
1. Ceiling. I'm pulling down the old ceiling.
Then seal all gaps in the floorboards above with acoustic sealant (please advise cheapest place to buy sealant - can I use standard bathroom sealant?).
Then RWA45 slabs chopped to fit between joists.
Then resilient batons attached to joists.
Then either 2 layers of soundboard or 2 layers of standard plasterboard. How much more insulation will soundboard provide?
I can't afford green glue to go between the layers, so just plan on screwing them.
Then skim the ceiling.
My main concern is
1. Whether to use soundboard or plasterboard
2. Are my joists strong enough to support all this?
They are approx 1"x 6.5" spaced 12" apart, they run across the room, so are approx 10'6" long.
Do I need to add extra joists?
My living room is above the music room, where the mrs and my kids will often be hanging out while I record, hence the need to soundproof as much as possible.
2. The walls
The walls are having all the plaster and render stripped this week due to damp. I am having them tanked and re-rendered, plastered. The walls that go onto my neighbours houses (we are mid terrace), I want to increase the soundproofing, so had been thinking of attaching 2 layers of soundboard to them prior to doing the final skim.
I can't afford green glue - are there any cheaper alternatives to go between the layers?
Shall I use resilient batons, attached directly to the render? I preferably wanted to avoid attaching wood batons, then plasterboard because I am reluctant to lose the space.
Am I still doing good by rigging up this plasterboard / soundboard if it's attached directly to the walls / resilient batons rather than building a full internal studd wall infront of the brick walls?
Again plasterboard or soundboard?
Which should I do first - the ceiling or the walls ie should the ceiling sit over the top of the walls or should the ceiling be surrounded by the walls?
If anyone can help me out I'll be very grateful - at the moment I feel the more I read the more confused I'm getting and I only have a few days to get materials in now!
:?
Many thanks in advance,
Sam[/u][/b]
Terrace basement: drywall riddle...
Originally posted at johnlsayers.com, topic 5897.
By "soundboard" what do you mean? There's no such thing is soundproof board you'd buy at the store. It's the combination of every day building materials that yields results in stopping sound. If you mean drywall, or gypsum board, then use that. Don't use actual plaster on the walls. You need multiple layers of drywall to stop the sound.
Your joists sound ok, but what's above them? If they're already supporting a waterbed you might want to consider adding joists. But 12 inches apart is really close by today's standards, mine are 16, so you already have more than normal.
Personally it sounds like you don't know enough about this stuff yet to have someone coming this week to do it. You'd probably benefit from holding off on having the guy come over until you know all this stuff. It takes a long time to really absorb this stuff and once you're done building isn't the time to learn it.
Clang-man gave you the best advice - don't do this til you know more. If you've been reading this board very long, you should have encountered a few repeats of the "soundboard vs. gypboard" question - the answer is MASS. Soundboard doesn't have it; gypsum DOES. There may be a slight advantage to using soundboard IF, and ONLY IF, you ALSO have at least three layers of gypsum in the wall ON EACH SIDE. Otherwise, you want the most mass you can get in each leaf of your wall.
"approximate" dimensions don't help - you need to actually MEASURE your joists - thickness, depth, spacing, and length, as well as type of wood if you can; otherwise no one can tell whether your ceiling will fall on your head or not.
We also need to know EXACTLY what your upper floor is made of - material, thickness, etc - this figures into calculation of maximum load you can have.
Some of the better grades of bathroom caulk might work, but they cost more for a 10 oz tube than the REAL stuff costs for a 29 oz tube. Another reason to slow down a bit, if you expect your place to STAY isolated after the caulk sets up - you can, if all else fails, order the right stuff online
good stuff
http://www.acousticalsolutions.com/prod ... /caulk.asp
Again, I would slow down, read more, and become the expert; your builder will NOT be the expert here, I doubt that 1 in 100 contractors on average will have ANY clue to the physics involved in isolation construction. I personally have NEVER talked to a "normal" contractor who had the first inkling of what to do, or what NOT to do. Not kidding.
If you rush, you WILL be disappointed in the results - that's one guarantee I feel really safe in making.
So please, read/re-read the articles in the REFERENCE section near the top of the Construction forum, actually MEASURE your framing, etc, and let's take this slow enough so you're actually HAPPY afterwards... Steve
If you ask 99,999 out of 100,000 construction workers what makes a wall soundproof, they'll tell you insulation. They haven't got a clue.
What do you think of this way of doing the ceiling: http://www.soundstop.co.uk/solutions/ce ... tion_1.php Thanks for the adviceBy "soundboard" what do you mean? There's no such thing is soundproof board you'd buy at the store. It's the combination of every day building materials that yields results in stopping sound. If you mean drywall, or gypsum board, then use that. Don't use actual plaster on the walls. You need multiple layers of drywall to stop the sound. SAM: Encon insulation http://www.encon.co.uk/index.html sell a product that's called SOundsheild, that I think is a heavier plasterboard. Is Gypsum / drywall the same as plasterboard? /SAM Your joists sound ok, but what's above them? If they're already supporting a waterbed you might want to consider adding joists. But 12 inches apart is really close by today's standards, mine are 16, so you already have more than normal. SAM: Living room is above with a sofa and one chair, not other furniture - TV is wall mounted. /SAM Personally it sounds like you don't know enough about this stuff yet to have someone coming this week to do it. You'd probably benefit from holding off on having the guy come over until you know all this stuff. It takes a long time to really absorb this stuff and once you're done building isn't the time to learn it. SAM: Well he's starting on removing a wall and hacking off plaster, so I have a few days to finalise plans for the walls and ceiling.
"approximate" dimensions don't help - you need to actually MEASURE your joists - thickness, depth, spacing, and length, as well as type of wood if you can; otherwise no one can tell whether your ceiling will fall on your head or not. SAM: My measurements are within a couple of millimeters. /SAM We also need to know EXACTLY what your upper floor is made of - material, thickness, etc - this figures into calculation of maximum load you can have. SAM: Upper floor is floorboards, not sure what wood, I'll have to take up some floor to measure the thickness, but might be able to do this from below, will let you know. /SAM Some of the better grades of bathroom caulk might work, but they cost more for a 10 oz tube than the REAL stuff costs for a 29 oz tube. Another reason to slow down a bit, if you expect your place to STAY isolated after the caulk sets up - you can, if all else fails, order the right stuff online good stuff http://www.acousticalsolutions.com/prod ... /caulk.asp SAM: Thanks - I'll get the real stuff. They might also stock it at Sheffield Insulation, who have a store in Bristol. sheffins.co.uk /SAM Again, I would slow down, read more, and become the expert; your builder will NOT be the expert here, I doubt that 1 in 100 contractors on average will have ANY clue to the physics involved in isolation construction. I personally have NEVER talked to a "normal" contractor who had the first inkling of what to do, or what NOT to do. Not kidding. SAM: I've been reading up on this for ages, probably should have posted here earlier, but I think the ceiling will be going up next week. I know need to be on the case this week ! /SAM If you rush, you WILL be disappointed in the results - that's one guarantee I feel really safe in making. So please, read/re-read the articles in the REFERENCE section near the top of the Construction forum, actually MEASURE your framing, etc, and let's take this slow enough so you're actually HAPPY afterwards... Steve SAM: Thanks Steve. I have read most of the articles, I can delay the fixing up of the walls and ceiling if necessary, but I think I have enough time to sort the materials out this week - with the help of you guys of course! /SAM
LOL. My neighbour is in his sixties and recently retired from a lifetime career as a professional builder. When I told him about my prospective studio build, he seriously tried to convince me that what I needed was egg-boxes all over the walls to stop the sound getting out. No question - he was sure of it. At that point I realised there was no point taking any notice of non-specialists in doing this.If you ask 99,999 out of 100,000 construction workers what makes a wall soundproof, they'll tell you insulation. They haven't got a clue.
Not to self: don't just go on what the builder says!
Is there anyone in Bristol / Bath UK who'd be prepared to come and advise me / have a look at the room?
Oh yeah, I'm not kidding. Yeah the numbers are funny, but they're more than likely very true. I work in the maintenance department at my job. When I talk to some of the mechanical maintenance guys about my studio they look at me so strange when I talk about sound proofing and sound control. Just the other day one guy who knows EVERYTHING started arguing with me about putting carpet in. He said "You should have carpet for acoustits!" He obviously thought this because when you're in a room with carpet and you clap your hands you don't hear as much echo. I tried explaining to him it does nothing for the low freq's and all that and he just couldn't understand. When I started planning my studio 6 years ago, before I knew anything about studio construction, every single person at work just told me to put insulation in the walls and that'd be all I'd need.
We recently renovated the front office and there were two conference rooms. This was built about 15 years ago. When we cut open one of the walls I was surprised as hell to see that there were two layers of drywall mounted on Z channel. Everyone was like "What the hell is this stuff?" And I had to explain. One guy, the Mr. Know-it-all told me I was being extremely arrogant saying I knew more than these guys about soundproofing.
The point of my story is, regular people just have no idea. There are so many myths about soundproofing that it's really hard to break through to people and make them understand. I've even been to watch a band rehearse where they literally had egg boxes all over every square inch of their practice room. I tried to explain it to them, but after eating nothing but eggs for 6 months they wanted nothing to do with the truth.
Oh yeah, and lulaboo, use two layers of drywall mounted on z channel, also stick the thickest insulation you can above it.
Thanks SC. Walls and ceiling? Is z channel, the same as resilient channel? I'm making enquiries about a structural engineer, to look at the joists and give me the all clear: SOS link I probably sound a bit gun ho about this, but I wasn't planning it as a studio build, it's a music room at home really, but as the date has come closer, my plans have expanded ie if I'm doing this why not do this. I had been thinking 2 layers of plasterboard all round, then discovered resilient channel, then got worried by the above post on the SOS site! So all the walls will be back to brickwork, then render, vandex for the damp, then plaster, then plasterboard... Or shall I skip the layer of plaster on the wall and add another leaf of plasterboard? Thanks for the surgery!Oh yeah, and lulaboo, use two layers of drywall mounted on z channel, also stick the thickest insulation you can above it.
Don't do plaster, just do two layers of drywall.
"z channel" is short for resilient channel. It's easier to type and spell. :D
I know you're not technically going to be using the room as a "studio", but if you're looking to stop sound the pricipals are the same no matter what you're doing. The laws of physics don't change because you're calling it a music room instead of studio. :)
Can the z channel go straight onto the render or is it more effective if it's attached to batons? 3 leaf even more effective? Are the outer layers also attached to the z channel or just to the plasterboard beneath? thanks SCDon't do plaster, just do two layers of drywall. "z channel" is short for resilient channel. It's easier to type and spell. :D
I'm not understanding your terms, I've just never heard them before. What do you mean by render and batons?
Do whatever you need to do on the wall of your basement. If you need a vapor barrier then use it. Then use studs to create the frame for your wall. Then put the Z channel on the studs and mount the two layers of drywall to the Z channel.
render - sand and cement that goes on the brickwork prior to plaster /or plasterboard
batons - studs
I'm asking if I can lose the studs - I have a door that opens beside this wall in the corner of the room which means I have very little space to play with...
Definitely don't lose the studs. What are you going to attach the Z channel to? If you're worried about losing floor space you could use furring strips. They're around $0.50 for a 12 foot length, they're metal, and work great if you're trying to save as much space as possible.
Sorry to disagree with you Sonic, but z channel is NOT the same as resilient channel. use REAL resilient channel. i was just reading thru Rod's book and he specifically IIRC warns against both hat channel and z channel. i don't have the book with me so someone correct me if i'm wrong.
in any case, nobody i've seen in a year on this board uses z channel (the thing OR the term) interchangably with RC.
and metal furring strips sound like hat channel, which is a definite waste of money and time, it won't do anything.
and definitely, 3 leaf is NOT better than 2 leaf. do not do this.
:D
I've always used the terms "resilient channel" and "z channel" interchangably and I've seen them described both ways. Watever term you refer to it by, it's a piece of metal that decouples drywall from the studs and/or OSB so vibrations don't pass from the drywall to the framework. Honestly I don't remember where I first saw them referred to as being the same thing, that doesn't matter.
And firring strips are not worthless, I beg to differ with you. They can be very practical if you're up against a brick wall that's backfilled with dirt on the other side and you want to save space. They're not intended to be like resilient channel. Their purpose is to act like a stud when you don't have the space to actually use studs.
EDIT: Here's one example of the terms being used interchangably. I just did a google search for "z channel".
http://www.djmart.com/ac101ba.html
Resilient Channel (aka "Z" Channel)
This is a piece of specially shaped metal to which drywall or other building materials can be mounted to isolate them from the framing members (studs) of a wall or ceiling. One leg of the resilient channel attaches to the stud, the other leg to the layer of building material being hung. This isolation helps improve the structure’s ability to achieve greater sound transmission loss
Sonic, ok, i just misread your mention of furring to be a substitute for RC. my bad. :oops:
as far as z channel, you are absolutely correct in that many MANY people use Z-channel interchangeably with Resilient channel. however it is not the same.
for example here's a cautionary note i found with a few minutes further searching, from the City of Vancouver Noise Control Manual, p. 57, under "Tips for Using Resilient Channel"
"Make sure you get true "resilient channel", or "RC-1" (see appendix C), as drywall contractors use many other metal channels and furring systems such as hat-channel and Z-channel which are intended for other purposes and are too stiff to have worthwhile noise reduction effects."
http://www.city.vancouver.bc.ca/engsvcs ... s/NCM1.pdf
Hope that helps clarify things a little.
Dan :)
Lubaloo,
I can certainly relate to your concern about space. I recently completed my home studio build which was intended as a band rehearsal room as well as for mixing and recording. As such, I was constantly concerned with how to save floor space (to accomodate more musicians) when considering the soundproofing techniques.
Partly because of practical problems that came up and things that went wrong, I ended up with a larger airgap between the two wall leaves than most people use - about 8 to 9 inches most of the way around. The room will be OK for most rehearsal purposes but I'm slightly disappointed I din't manage to get it bigger.
However on the upside, the soundproofing results are fantastic - I'm talking almost total isolation even at high listening levels. (I've recently posted about this here and at SOS). Which will be really handy for rehearsal purposes because I'll know we can play whatever we like whenever we like, and it needn't affect anyone.
Early on in my build, when one of the things came up that meant the room looked like being smaller than I wanted, I did briefly enquire around about making it a single-leaf structure instead, and just beefing up the single wall with as much mass as possible. I was advised not to, so didn't. But whether I would have gotten results that were "good enough" that way, and saved a lot of valuable internal real estate, I don't know...
I think to make a judgment like that you'd really need to look at detailed isolation specs on different types of materials and approach it more technically. The only way to be confident you're going to get decent isolation without doing this is to build a true mass-air-mass system. This means that the two leaves of mass have to be genuinely decoupled (ie, your plasterboard has to hang on studs which are not in direct contact anywhere with the outer wall). And this, unfortunately, takes up space.
You might consider coming up with your maximum practical single, non-decoupled wall. ie what you would get with your current wall beefed up with render, a few layers of plasterboard etc. With no airgap at all. Then see if you can enlist some help here, at SOS etc, in calculating the isolation spec of such a wall. Then get some feedback on how such a spec would translate to the real world (eg, "bass drum above 90db would be just audible a few metres away, above 100db would be quite noticeable", etc etc.) And if this seems enough to you, do it and save the hassle and space required for a more complicated build.
That's what I might have done had I been prepared to spend the time researching it more fully. But I wanted to get on with things and just sacfificed the space instead.
Don't forget too that factors such as doors, windows and ventilation will have a huge effect on soundproofing, and need to be consider in any such calculations.
well I've been reading all evening, and I'm getting clearer Thanks for all the comments. Also thanks Rod for your comments on the SOS site - I'm trying to find an engineer who can come in at short notice ie tomorrow or weds. If anyone knows one based in Bristol let me know!
So, as you suggest Wurlitzer, I don't think I can de-couple the studs and the brick wall, and might have to use very thin studs. The main problem I have is that the door into the room opens directly in the corner, so there's no room for it to open if the wall gets much thicker. It could be moved onto the other side of the frame, but this is awkward as there are stairs there, and it won't open properly that way.
Current plan:
Thick layer of render on the walls followed by 2 sheets of plasterboard on resilient channel on thin studs.
Question: Should I skim the room when it's finished? Aesthetically I'd like to but if I cover the joints that I've carefully caulked will that destroy the de-coupling?
Another issue I'm wrestling with at the moment is that my electricity meter box and fuses are on the back wall of the studio room with a home made wooden box around them. It would cost me £300-£400 to have this moved, which means I'm going to leave it there (having deceided to fork out for an engineer). My new stud wall will have to surround this box... What's the best way to deal with it?
Shall I wrap it in 2 layers of plasterboard? Is it OK to make it airtight? I don't think I will be able to remove it from the wall and then attach it to my new wall.
TBC, big thanks for the tips Knightfly, Dan, Wurlitzer, SonicClang
lubaloo, you have to be careful when adding gypsum directly to brick, you really need to do it without ANY air gaps between the gypsum and the brick (or render). at least, this is true if you want to isolate low frequencies see this chart below.
this data is from IR-586 and shows the effect of drywall (gypsum) directly applied to block wall WITHOUT any furring (just directly screwed on). even the tiny gaps that occur do to irregular surface give worse iso from ca. 200 hz to 400 hz by around 5db. of course above that everything's great, +8 db or so.
see this post for complete comment.
http://www.johnlsayers.com/phpBB2/viewt ... 0374#30374
what would happen with a 1/2 inch gap i can't say for sure, but it would almost surely hurt performance, most likely at a lower frequency than this example.
isn't it amazing that you can add 2 layers of gypsum to a block wall and HURT performance over a range of frequencies? watch out!!
dan
Thanks Dan - although now it's getting more confusing :(
BTW what is 'mud'? I've searched but not found....
How is your baby you mention your wife is pregnant in the other thread... I had my 2nd in Nov, which is making the build a little bit slower ; )
I've never worked with resilient channel and don't know anything about it, so I'm going to bow out and leave this to those that have and do.Current plan: Thick layer of render on the walls followed by 2 sheets of plasterboard on resilient channel on thin studs.
No, it won't destroy the decoupling at all. It may help very slightly by further covering the joints.Question: Should I skim the room when it's finished? Aesthetically I'd like to but if I cover the joints that I've carefully caulked will that destroy the de-coupling?
Plaster - used to cover over the seams between sheets of tapered-edge plasterboard. You bring the sheets up flush to each other, then apply plaster over the tapered part, bringing it up to the level of the rest of the sheet and sealing the joint at the same time.BTW what is 'mud'? I've searched but not found....
Thanks for asking Lubaloo ... you must have seen an older post, the baby is now just over 6 months old, born in Sept. Congrats on your second!
For those of us with kids, the studio can double as a "panic room" for when you just can't take it anymore :lol:
I don't have kids, but just being married can be enough sometimes. :) my studio is my domain, and my wife understands that. It's my sancuary.For those of us with kids, the studio can double as a "panic room" for when you just can't take it anymore :lol: