Treatment for Porl and Patrick

[John Sayers]

I've posted this here so everyone can have a go at it

We are planning to build a vocal/drum booth in a factory building that has
been block partitioned into media studio units. We are trying to achieve an
STC rating of around 60 with particular emphasis on bass transmission
reduction (e.g. bass drums). Both myself and my partner have any previous
building experience ­ the plans we have have been culled from various
sources on the net. We would appreciate any feedback about their possible
effectiveness or suggestions for improvements.


With reference to our plans we are seeking advice about the following:

Wall Questions:
Are there any gains to be made in alternating MDF and plasterboard
Are 25 gauge steel studs going to be strong enough to support our walls
What are the steel studs and tracks attached to (i.e. do we need to build a
frame for them or can they go directly onto the ceiling and floor) Also,
what is the recommended way to attach them in order to preserve the
decoupling effect
Could you recommend anywhere that we can find drawings illustrating the
best construction methods for joining stud walls at the corner
Re: staggered studs, does it matter if at any point stud in the two walls
are parallel to each other
What sort of glue is used to glue plasterboard to MDF
Is there a preferred method for screwing MDF to studs



Floor Questions:
Is the sand fill idea acceptable as an alternative to using concrete
How would the STC rating compare if our floor was floated on neoprene studs
as opposed to the 705 rockwool
Is 4" of 705 sufficient to float floors in this way or would different
thicknesses and densities fare better
Should the rockwool need to be glued to the floor or does it need a frame
to keep it in place (not attached to the structure of course)
Is our floating floor going to support our room
Is our floor joist spacing ok



Ceiling Questions:
Is there a particular spec for the resilient channel that we need to look
out for
Will the resilient channel support the shown thicknesses of plasterboard.
Will it be acceptable to attach the top leaf of plasterboard only to the RC
and glue the rest to the top leaf




General Build Questions:
We need 1 powerpoint inside the booth to be taken from the outside room.
Would it be better to run this cable through our floating floor or through
the wall
Our booth is slotting into an identical existing space and we are confused
about the order in which we need to build things. Our current rationale is
to build the floor and ceiling first and once they are in place, build the
walls. What is your opinion about this

Many thanks in advance.

Porl and Patrick

[knightfly]

Porl and Patrick - I've seen entire books on acoustics that didn't cover the range of information you're looking for - be advised that this is going to take a while, with a lot of questions both ways -

First of all, your statement "Both myself and my partner have any previous building experience ­" - could you clarify that - do you mean that both of you have SOME experience, or that both of you have NO experience, or what?

Second, I can see that you've been exposed to some mis-conceptions as to what works for sound isolation. We can clear those up, one at a time. You seem to have most of it right...

As long as your list of questions is, I think the least confusing way to approach it is to copy your post and then fit my answers in between - here goes...

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

We are planning to build a vocal/drum booth in a factory building that has been block partitioned into media studio units. We are trying to achieve an
STC rating of around 60 with particular emphasis on bass transmission reduction (e.g. bass drums). Both myself and my partner have any previous building experience ­ the plans we have have been culled from various sources on the net. We would appreciate any feedback about their possible effectiveness or suggestions for improvements.

*Given your statement about STC 60, followed by reference to bass drums, I'd be willing to bet you'd come closer to wanting STC 70 or better. Keep in mind that STC takes NOTHING into account below 125 hZ, and an STC 60 wall would only have a Transmission Loss at kick drum frequencies of around 35-40 dB. This means that, if you're playing drums in the room and the kick is at 120 dB, subtracting 40 from that would still make it about 80 dB outside, 70 dB at best. Accomplishing that will take more mass and probably more air space than you've shown.

With reference to our plans we are seeking advice about the following:

Wall Questions:

Are there any gains to be made in alternating MDF and plasterboard -

*Yes, dissimilar materials disrupt sound transmission more.


Are 25 gauge steel studs going to be strong enough to support our walls -

*USG make special "load bearing" versions of their studs that have reinforced webs. Those would work, but you may need to go wider.


What are the steel studs and tracks attached to (i.e. do we need to build a frame for them or can they go directly onto the ceiling and floor) -

*For the kind of isolation you're looking for, the answer would be "some of each" - the outer wall should be set in something like SillSeal and caulked with acoustic sealant, its lower channel Ramset or lead anchored into the concrete - then, the inner wall should be floated on the floating floor, set the same way and screwed down.


Also, what is the recommended way to attach them in order to preserve the decoupling effect -

*I would need to know more about your space first - for example, what is the overall height you have to work with, from existing floor to existing concrete ceiling joists? With the isolation you're looking for, we need to look at a totally floated, fully independent room-in-a-room. In addition to your detail drawings, I need a rough floor plan with dimensions in ALL THREE planes, not just length and width.


Could you recommend anywhere that we can find drawings illustrating the best construction methods for joining stud walls at the corner -

*I'll probably have to draw them for you, as staggered studs aren't going to get you as much isolation as you want.


Re: staggered studs, does it matter if at any point stud in the two walls are parallel to each other -

*See above - normally, staggered studs are placed on a common plate and cap that are wider than the studs, but it's still common to inner and outer studs. Not good enough.


What sort of glue is used to glue plasterboard to MDF -

*Generally NONE - with multiple layers on a wall frame, you want each layer to be able to independently flex but without an air gap - this increases the Transmission Loss due to the combination of more heat conversion from sound energy, and more loss due to refraction at layers, propagation speed changes in different materials, and different resonances of the various panels.


Is there a preferred method for screwing MDF to studs -

*Generally NOT to - you're going to need more mass, and usually triple layer walls start and end with plasterboard. The first layer of panel on the wall frame should be bedded in a bead of acoustic sealant to avoid rattles - Successively longer wallboard screws are used for each additional layer. The newer screws have heads that look like a combination phillips and square drive, each box of screws comes with its own driver bit. Killer grip, won't strip out the heads unlike philips. Make sure you use actual drywall screws SPECIFICALLY for STEEL studs, both for resilient channel and for the steel studs, or you'll have problems. As far as the MDF goes, it's quite hard and should be drilled with an all-in-one type pilot bit SPECIFICALLY sized for the screws you use - make sure each screw goes in far enough NOT to make the succeeding layer of wallboard stand away from the MDF layer.



Floor Questions:

Is the sand fill idea acceptable as an alternative to using concrete -

*To ALL your floor questions, I'll have to say you should start over. You've designed a floor that will probably AMPLIFY outside sounds instead of attenuate them. Whether or not you use concrete for the top layer, almost all of the stuff in between the existing floor and the top is wasted time, money and effort. I'll explain more in a day or two. I'm headed for some pillow time soon, and that subject is very involved.


How would the STC rating compare if our floor was floated on neoprene studs as opposed to the 705 rockwool


Is 4" of 705 sufficient to float floors in this way or would different thicknesses and densities fare better


Should the rockwool need to be glued to the floor or does it need a frame to keep it in place (not attached to the structure of course)


Is our floating floor going to support our room


Is our floor joist spacing ok



Ceiling Questions:

Is there a particular spec for the resilient channel that we need to look out for -

*Yes, but first I need to know how far apart those concrete joists are, and how you intend to/(are allowed to) fasten to them.


Will the resilient channel support the shown thicknesses of plasterboard. -

*Depends on your answer to the previous question...


Will it be acceptable to attach the top leaf of plasterboard only to the RC and glue the rest to the top leaf -

*Only if you promise to invite all my least favorite politicians to your open house party :=) - Seriously, I don't think it's even LEGAL to do that. I know we fly around in airplanes that are "glued together", but I wouldn't want to live under such a ceiling.




General Build Questions:

We need 1 powerpoint inside the booth to be taken from the outside room. Would it be better to run this cable through our floating floor or through
the wall

*Thru the floor, it's easier to get it where you need the power and you can do a better job of keeping sound loss to a minimum.

Our booth is slotting into an identical existing space and we are confused
about the order in which we need to build things. Our current rationale is
to build the floor and ceiling first and once they are in place, build the
walls. What is your opinion about this

*I take it from that that you mean to suspend the ceiling from the existing structure - wall construction could get tricky where there is a neighboring wall. When you draw your floor plan, please include details about what is already there as well as what you want to add.

Many thanks in advance.

Porl and Patrick

OK, as soon as you answer all my questions and do a floor plan as I asked above, we can get to the next round... Steve

[John Sayers]

Well done steve - everyone give steve a cheer :)

cheers
john

[knightfly]

Not finished yet, think I'll just copy this thread later and start shopping for a publishing deal...

[porl]

Many thanks for the replies so far especially from Knightfly. It's been very illuminating.
To answer your questions one by one:

First of all, your statement "Both myself and my partner have any previous building experience -" - could you clarify that - do you mean that both of you have SOME experience, or that both of you have NO experience, or what?

Neither of us have any building experience.

Also, what is the recommended way to attach them in order to preserve the decoupling effect -

*I would need to know more about your space first - for example, what is the overall height you have to work with, from existing floor to existing concrete ceiling joists? With the isolation you're looking for, we need to look at a totally floated, fully independent room-in-a-room. In addition to your detail drawings, I need a rough floor plan with dimensions in ALL THREE planes, not just length and width.

We have drawn up some new plans for the space in which we will be building the booth.We are having trouble attaching images to this message so here is an external link to them including a few photos of the ceiling detail. FYI. We are building a double leaf wall with staggered studs as opposed to staggered studs on a common plate.
http://www.btinternet.com/~samandporl/plans.html

The first layer of panel on the wall frame should be bedded in a bead of acoustic sealant to avoid rattles

Do you mean like a fridge door type seal or are you simply referring to acoustic caulk?

Is there a particular spec for the resilient channel that we need to look out for -

*Yes, but first I need to know how far apart those concrete joists are, and how you intend to/(are allowed to) fasten to them.

We have included the joist distance on the plans.As far as the building managers are concerned there don't seem to be any restrictions as to how we are allowed to attach resilient channels to the ceiling. Please could you let us know if resilient channels are the best way to go, or is there an acceptable alternative?
We look forward to your comments on why our floor plan won't work and what alternatives would work.
Thanks in advance
Porl and Patrick

[knightfly]

Thanks for the drawings/pix - I forgot a few other questions I had, such as -

What is your budget?

Do you plan to get any experienced help, or is it just the two of you?

What general part of the world are you in?

Has anyone done a Noise Study in the building (how loud, how often, when)- How much noise is around you, and how picky are your neighbors?

Which is more problem, noise getting OUT or noise getting IN? (Construction isn't one-way, I just need to know in order to determine the degree of isolation REALLY needed)

What is ABOVE your space? Is there noise coming from there, or picky upstairs neighbors?

Your finished INSIDE dimensions are going to end up almost half a meter smaller than they are now, are you REALLY going to put a full set of drums in there along with recording gear?

Answers to your questions so far -

"Do you mean like a fridge door type seal or are you simply referring to acoustic caulk?" - Just referring to acoustic caulk.

Resilient channels for the ceiling may NOT be the best way to go - it might work better if you were to build a completely independent floated room, with its ceiling supported on its own walls.

The floor - What you've drawn is at least a triple, if not quadruple, leaf partition. The concrete it's sitting on is arguably the first, then the layer of particle board, then the layer of MDF, and finally the second layer of MDF. It's possible that, assuming you vibrate the structure enough to settle the sand enough and strike off just barely enough sand to get the top layer of MDF on, WITHOUT creating a miniscule AIR space, that it would only be a triple leaf partition.

Anything more than two leaves with ONE air space between, is poor use of materials and will LOWER the isolation by as much as 20 dB and sometimes a little more.

For less time and money and effort than that, you could have a floated concrete floor built, like this

http://www.kineticsnoise.com/architectu ... nstall.pdf

Or you could do it in wood, putting ALL the mass in the top layer, like this

http://www.kineticsnoise.com/architectu ... nstall.pdf

If you use the optional stringers over their pads and under the flooring(see the second picture down)

http://www.kineticsnoise.com/architectu ... floor.html

it would leave room for a wiring trough or conduit - this would have to be caulked thoroughly at BOTH ends after wires are in place.

These are just examples - there are other companies in the world with similar offerings, none are cheap but they work. As soon as I find out what part of the world you're in, the search could be narrowed down.

Yet another option would be something like Auralex U-boats, although loading would have to be carefully calculated to get best performance.

On another note, please read this

http://johnlsayers.com/phpBB2/viewtopic.php?t=502

I'm still looking for info on adhesives and alternate ceiling laminating methods, no luck yet... Steve

[porl]

Thanks again Steve for your continued input. The links are really useful.

We are planning to the effect that we will receive no experienced help in the construction of our studio. We have people that we can seek advice from but as for the practical building, it will more than likely be just the two of us.

We are in the process of obtaining some illustrated step by step "building a booth for beginners" style literature. Our approach to all this is to gather as much information as possible before we start to build and do as much planning as we can - hence all the questions. Any recommendations for literature will again be gratefully received.

A few of your questions I can answer straight away.

I think our initial gut feeling was to build a booth to keep out exterior noise. We ran a preliminary db test in the room earlier this week. The building itself is generally quite quiet (adjacently populated by artists, sculptors and increasngly more musicians albeit on other floors). The noise problems tend to extend from outside. When we ran our db check we had a commercial aircraft flying overhead at the same time as a train going by about 300 yards away and builders working below with our windows open !
The meter reading was about 70db so I guess you could say that would be a worst case scenario. Normally it was registering about 45 - 55

I should point out that during the time that our neighbours are occupying the adjacent spaces, we will be limiting our recording to mainly voice-over type stuff. On the occasions that we will be recording drums either our neighbours will have gone home or will have been consulted first (all pretty reasonable folk). All in all our noise levels can be quite flexible. The only reason for the extra proofing would be for the commercial possibility of hiring out the room to people who may wish to record drums during the day.

Our budget is probably our sticking point - we have a nominal figure of £1000 at the moment. We may be able to get funding elsewhere if it's really necessary.

I think the lowest spec we could accept is to build a booth in which we can record a spoken word vocal during the day uninterrupted by our outside noise. The drum option would be preferable if it can be done for the kind of money we could feasibly raise.

If it's possible for you to give us an educated guess costing for the "vocal" or "drum" option - that may help us to be a little more decisive.

We are in London, England.

Thanks again,

Porl.

[knightfly]

Porl, that's good news on the sonics, maybe not such good news on the budget - It was 1967 the last time I was in London, the pound was worth $2.82 US, and I wasn't looking to build anything (other than perhaps international relations )

Sooo, in order to get a better idea of costs (you're going to have to do this sooner or later anyway) you need to find out what materials are costing there (Sterling is fine, I can add to 1000 )

The main materials you need to price are

gypsum wallboard in both 12 and 16mm (and what size sheet that is),
19mm MDF, probably in 2439mm x 1220mm sheets
28 mm tongue and groove floor plywood, or the "waferwood" type, same size sheets
4"x2" framing studs, or steel, 37mm x 100mm 25 Gauge if you intend to go that way
10"x2" framing for ceiling joists
8"x2" timbers for floated floor joists

That should do for now, it'll at least let us get a ballpark figure... Steve

[porl]

Dear Steve thanks very much for the quick reply.
We have some prices from a local building merchant here in London:

plasterboard (gypsum wallboard) 2700mmx900mmx12.5mm £13.70
plasterboard (gypsum wallboard) 2700x900x15mm £15.58
tongue and groove floor plywood 2440mmx610mmx22mm(we couldn't find 28mm thickness)£8.16 per metre
4"x2" framing studs ££2.50 per metre
10"x2" framing for ceiling joists ££8.00 per metre
8"x2" timbers for floating joist floors £7.00 per metre.

There are other miscellaneous prices which we thought might be useful:

neoprene 15mmx13mmx1000mm £5.00

neoprene 13mmx3mmx1000 £1.00

U-boats width 54mm height 38 mm slot width 38mm slot height 30mm £3.30 each

rockwool RWA45 45Kg/m3 (703 equivalent) 1200mmx600x30mm £2.65 each, 50mm thickness £3.75 each,75mm thickness £5.66 each

rockwool RW3 60kg/m3 (705 equivalent) 1200mmx600x30mm £3.10 each
50mm thickness £5.00 each, 75mm £7.66 each

rockwool RW6 140Kg/m3 (don't know the US equivalent density)1200mmx600mmx30mm £8.33 each
50mm thickness £12.50 each, 75mm thickness £16.00 each.

We have calculated all the prices to include Sales Tax.

Just to clarify things in case you thought we were trying to squeeze allour gear into a tiny space this is just for our drum booth. Our control room is next to it and measures: 7.5mx5.5mx3.9m,but we don't intend to be monitoring loud,so we won't be soundproofing that room just yet.
Thanks as always for your advice. Look forward to hearing from you.

[porl]

Sorry i forgot the price for The MDF which is 22mmx3050x1220 (the nearest size thickness we could find ) £60.00 each.
Cheers

[knightfly]

Porl, when you say "per metre", do you mean a LINEAL metre, or a SQUARE metre? You gave prices on particular sized sheets, then added the "per metre" designation. Can you clarify those details for me?

Also, I'm glad that is just your drum booth, I was starting to get worried there for a bit...

[porl]

Hi Steve,

To clarify-

MDF, Plasterboard, Plywood, Rockwool & Neoprene are all prices per sheet. (Dimensions indicated)

Timber framing & joists are prices per linear metre

U boats are unit prices

Apologies for the confusion

Cheers,

Porl.

[knightfly]

Porl, when I finally got the chance to convert your material prices to something I am familiar with, I was stunned - your price per square unit on wallboard is roughly 5 TIMES what it is in my location on the West Coast USA - I then did some rough calculations, and discovered that three layers of wallboard just for walls, no framing, no ceiling, and no floor, would run around 700 pounds (sorry, I don't have the cool L on my keyboard)

I don't see how you could stay anywhere NEAR budget with those prices.

Another thing - you drew walls using steel studs, but didn't mention pricing for them - that could save quite a bit over wood, since your price for 1 meter 4x2 is about 25% higher than our cost for an entire 8 foot stud.

Are there any cheaper materials available to you than gypsum wallboard and plywood? What about masonry products? What you need is something with lots of MASS, without a king's ransom for a price tag. Otherwise, it's looking more like 2000-2500 pounds for the project... Steve

[porl]

Steve,

"rip off britain" has been a political hot potato for some time! The expense is not surprising - we arrived at £2.5k too with our original designs. As I said our budget could probably go to that if needs be. The hope is that cold hard cash will level the playing field......

We would like to go with the timber ceiling and floor designs on the SAE site as we know where we are with them. What are your thoughts?

What we need to nail is the wall designs.

Please could you let us know what your recommendations are for these? believe it or not the 4"x2" timber studs actually come in cheaper than steel studs at the prices we've been quoted. We would like to stick with them if possible.

Also could you let me know where the 2"x8" and 2"x10" timber comes into the equation ?

If you could let us know these, we can go away and draw up some new plans.

many thanks,

Porl.

[knightfly]

Porl, I'm still getting over the "sticker shock" on your pricing - do you mean to tell me that the lightweight, 25 gauge steel studs are as ridiculously priced as wood 4x2's? That's even scarier than 5x costs on drywall panels...

OK, now you're really confusing me - at first, you were saying you were thinking of doing the ceiling/floor first and then the walls - this would require that you use a suspended ceiling, and yet none of the designs I've seen on the SAE site are suspended ceilings. Also, specifically WHICH floor (or ceiling, for that matter) designs were you looking at?

Next, before I can recommend wall construction there are a few more questions - these existing block walls - are they hollow block, or filled, or solid, ??? The couple of actual pictures you posted helped a lot, but there are still other questions - on the existing ceiling joists, are they all the same height from the floor or is the main, wide one deeper (vertically) too?

On the existing single wooden partition wall, could you describe its construction in more detail? (materials, sizes, condition - are there any holes, etc, does it go completely to the ceiling joists, is it sealed to them, ANY DETAILS you can think of, don't assume ANY detail is not worth mentioning.

As to the 10" and 8" timbers, I was thinking about using the 8" for floor joists supported on U-boats and the 10" as ceiling joists for a ceiling that bears on the walls but with neoprene under. Given the pricing you have, however, leads me to question whether a floated concrete floor might cost less and work better, and whether a resilient hangered, 6x2 framed, double layered (12mm and 16mm) drywall ceiling with heavy insulation above might be the way to go.

Have you checked for price and availablity of single-legged resilient channel, such as the RC-1 shown in illustrations in the USG manual (linked to at the top of this forum) ? What I'm thinking of for your one wall that will be built from scratch, is (from inside to out, going TOWARD the control room) 12mm wallboard, 16mm wallboard, resilient channel, 4x2 stud frame (all resting on floated floor, sealed w/acoustical sealant) then 4x2 stud frame (resting on original floor, fastened with construction adhesive, thick enough beads to seal irregularities in floor, caulked with acoustical sealant) then 16mm drywall direct on studs (run a bead of acoustical sealant down each stud face before fastening, levels out irregularities) then 12mm Celotex soundboard NOT SCREWED TO STUDS but LAMINATED to 16mm drywall using slightly thinned joint compound and laminating screws (USG type G or equivalent) and finally a layer of 12mm drywall, fastened ONLY in rows parallel to (but NOT coincident with, just close to) the framing studs. Cauld EVERYTHING as you go, with REAL acoustical sealant - use spacers on bottom panels so that you leave a gap of about 3-4 mm - after panels are mounted, pull out the spacers and caulk with acoustical sealant.

A better description of the mounting of the inside, final layer of wallboard - put your 3-4mm spacers along the bottom of the wall; on the soundboard layer, spread a thin layer of joint compound 100mm wide, directly over, and centered on, the vertical studs. Put the final layer of 12mm wallboard up against the soundboard layer, and fasten ONLY with Type G or equivalent LAMINATING screws, and ONLY in a vertical line 50-75 mm offset from the stud. You will only need one laminating screw every 300-400 mm, since the joint compound will take a lot of the job of holding this layer in place. Pull the spacers and caulk as usual.

The idea on this side of the wall is to NOT attach successive layers with fasteners that penetrate the studs, or you will lose isolation. This is NOT the case on the other side of the wall, where the Resilient Channel is your isolation from studs.

I'll get back with a drawing on this, but I owe Luke one first and it's not done yet either - stay tuned... Steve