Basement studio-room project in Boston area

[Luftweg]

Quick update....

In the process of sistering the 2x8 joists; bought the new ones today which are 14' spruce-pine-fir #2...
They will be glued/screwed to the old ones.
Every joist will be sistered from over the sill to over the center beam
(the areas are 'clear' from any electrical, plumbing; there is only the main heating duct (but it's not really in the way at all); I'm lucky that I have good access).

This appears to be mostly a precautionary measure, as the above floor is not saggy or bouncy, but when the 2 layers of 5/8" sheetrock go up who knows? (although, from what I've been seeing on span tables, it might still be 'okay' without them -- but nearer the limit of still being okay... that is if the old ones are at least #2's, which they definitely appear now that I've made comparisons).

The new joists are 1/4 inch deeper than the old ones.
I will have to notch the ends in some manner to fit over the sill and center beam.

After the sister act, solid 2x8 blocking will be put in to replace the cross-bracing.
I'm going to put these in BEFORE the layers of sheetrock are added..... I think...

**** Is there any reason that I should put the blocking in AFTER the sheetrock is added?
There's nothing about this that will affect any caulking seals, is there? (although of course there will be more of them, which isn't the best thing)

Before sounds better since it appears less likely the sheetrock or any caulk seals will get disturbed by the tauma of blocking in...
Also, I will have to notch the blocking to allow room for the inner-leaf ceiling joists (so having them in first allows a greater depth of blocking.... if they were done afterward, they could only be 2x6 blocking, and the notching would further compromise them).
So of course, the strips of sheetrock will also be shorter.

Finally, I also bought the 5/8" sheetrock enough for both layers of the outer leaf ceiling.

Damn. I guess I'm gonna go for the Green Glue too?
I don't know exactly why, but this stuff 'feels' like it could be a scam in a way..... then again I have no direct evidence to support that notion -- it's just the whole marketing of it that seems suspect in some way....

If I do get the GG, I will almost write it off as 'possibly' being a waste, and then hope I'm wrong -- but how would I ever be able to tell the difference anyway? how does ANYONE know?

K

[sharward]

Go over to studiotips.com's forums, and you'll find several threads there where Green Glue has been challenged and its claims have been proven with independent lab tests. I too was a little skeptical at first (as we all have to be when it comes to "sound proofing products"), but that stuff is the real deal.

[Luftweg]

Go over to studiotips.com's forums, and you'll find several threads there where Green Glue has been challenged and its claims have been proven with independent lab tests. I too was a little skeptical at first (as we all have to be when it comes to "sound proofing products"), but that stuff is the real deal.

Oh geez, I must have read a few of those such threads...
In fact, I found them because I had read an earlier post by you, linking to them... thanx Sharward.....

In other news, today I picked up 6 sheets of Johns Manville 1 inch SuperDuct board; each sheet is 4' by 10'....
It costed $1.71 a square foot.
Part of these will be used replace the existing galv. steel ductwork above my studio area; the rest will be used to construct ventilation for the studio itself...
Planning on making a little 'buffer room' adjacent to the studio, which will contain most of all the 'required' duct length and 180 degrees of bends to allow the superduct to absorb much of the escaping sound....
Looking into perhaps using reverse-flow auto muffler design aspects to see if there is a way to make it as compact as possible.

Because the basement is dehumidifed and is naturally cool 365 days/yr (and do my pet chinchillas love that!), and because I won't be operating tons of equipment, I will at first just 'equilabrate' the studio air with the air of the rest of the basement.
If that's inadequate, then I'll take it from there, but at least the ductwork will be in place already.
The studio will be a one room design, and as such I'm only planning putting in one big inlet and one big outlet.

Hopefully I can have have all the above floor's joists sistered by this weekend....
I better order the Green Glue so that I can have it for the inbetween joists sheetrock layers...

OH, now that I will be sistering the joists, I wonder if I should plan for THREE layers of sheetrock between the above joists?
The floor should be able to take that I would think, as there will be TWO 2x8 #2 northern hem-fir joists per each 16 OC spacing..... (?)
Plus, once I put up the inner-leaf ceiling, I won't be easily able to go back and add another layer.... yet I WOULD still be able to add another layer to the inner-leaf ceiling and/or any of the walls...

K

revision: the sister joists are spruce-pine-fir, NOT hem-fir (as I could not find these).... the originals ARE very most likely northern hem-fir, and I can tell already that they are harder than the new s-p-f, and probably alot stronger too...

[sharward]

[Because the basement is dehumidifed and is naturally cool 365 days/yr (and do my pet chinchillas love that!) . . .

Did somebody mention chinchillas?



Meet Gonzo, Gizmo, and Libby -- a daddy and two sons from different litters, all black velvets. Gonzo's at least twelve years old now, and the boys are about eight and five. (We lost their mommy about five years ago. )

Chinchillas are cool!

. . . and because I won't be operating tons of equipment, I will at first just 'equilabrate' the studio air with the air of the rest of the basement.
If that's inadequate, then I'll take it from there, but at least the ductwork will be in place alread.

Sorry, but I don't think that's going to fly. I'm pretty sure code calls for mechanical ventilation directly from outside when there is no window. Talk to your local building department.

Don't assume that you'll be able to tweak your ventilation system to meet code later -- you must design the space with ventilation as an integral component in the design. Retrofitting later can be extremely costly, in terms of money, space, isolation, or any combination.

Also, I would hold off on modifying your ducting until you have your permit, because those changes will probably also require an inspection. It's tempting to do something, but don't get ahead of yourself and end up having to reverse things later.

--Keith

[Kathy]

Hiya Luftweg!

Just read thru your thread and wanted to say that I think you show great attention to detail and because of that you are going to have a superb outcome, no matter what roadblocks you may have or what you encounter to get there. I have no doubt that you are one who succeeds.

And hey, I thought MY posts were long but I think I've met my match!

Also, I feel a little neighborly love towards ya.....I'm just a holler away up here in NH. I was born in Salem, MA and love the Saugus area and all the nifty things it has to offer. I'm there a couple of times a month just for the Christmas Tree Shop alone!

Lastly, I have just about nothing to offer in the way of advice since I'm hobbling along here as a newbie and my entire barn conversion has been aided along by this forum as well. The questions you ask are way over my head as this is a virgin project for me. But perhaps you can benefit from my mistakes/journey or my own questions that were answered. If you haven't already visited my thread it's called Kathy's Barn Conversion!.

Nice to see a local!

[Luftweg]

Did somebody mention chinchillas?
...
Chinchillas are cool!

There must be something about studios and chinchillas?..... Cute family of chinchillas there! .... Black velvets are definitely my favorites.....

Anyway, I have 2: Lola and Manni (the main characters in "Run Lola Run")... they are 3 yrs old...

Here is (somewhat younger) Lola getting ready to take a bath....
(note that her whiskers have been chewed down a bit by Manni.... he doesn't do that anymore and they are now rightly very long)

K

[guitardad72]

Hmmm,

Previously I've owned 2 chinchillas. Almost got another one last year but decided my son was to young for that type of pet, so we got a cat.

Well now that we are completely off topic...

Keith... have you had any problems with cats and chinchillas in same house?

And I'll share a chinchilla tragidy story, one of my personal worst moments.

1st Chinchilla, Blacky we (old girlfriend, her son & I) got from a pet store. It was about a year old and was not kept at pet store in the correct cage, it was in a glass cage... making the chinchilla a little wild (and it had other problems). We let the blacky run through the house, but unlike the our 2nd chinchilla, Blacky would not eventually go back in the cage (which I built correctly). So, one morning Blacky was under the stove, girlfriends son at age 8 would jump to startle the chinchilla and get him out from under stove. Well instead of the jump and Blacky running the other way... it was the jump, Blacky ran under the sons feet and the son landed in Blacky and killed his own pet. We woke up to screaming and that day really sucked.

Within a week we got our 2nd Chinchilla "Boots" at a few months old and he was raised great and was friendly. Boots is now in a happy home in Canada, as we had to give him away.

Once my son is older I do plan to get another Chinchilla, which is a cute, non smelly, quiet pet.

Marc

[sharward]

Oh, what a horrible story! That had to have been awful.

Our chins don't run loose in our house. We have large cage (30" x 30" x 24") for them, and one of similar size for our bunny. We handle the chins occasionally and we always make sure the cats are a safe distance away.

There have been a couple of times that a chinchilla has gotten loose without our knowledge, and they seemed to not get chased by any of the cats during those times!

I do have a couple of chinchilla tragedies of my own, but I won't share them here... Maybe in my own thread someday if the chinchilla subject comes up. Sorry for the chinchilla hijack (ooooh, band name maybe? ).

--Keith

[Luftweg]

Update:
Joist sistering almost done, and looks very good.
Will be soon blocking mid-spans between joists (possibly at thirds).
I did slightly 'load' the sister joists by raising them a tiny bit while gluing and screwing them together (one joist at a time).

Planning on adding 3 layers of sheet rock between the joists because the above floor must certainly be able to 'take it' with EVERY joist now doubled up.
(I would have this checked out with BA)

Also, no sheetrock would be suspended from below the joist (via RC or otherwise), so there would be ONLY 3 layers of sheetrock TOTAL (and these would be 1.5 inches narrower strips, due to the added joist width).
Hmmm, should I add a layer of the 1 psf lead I have?

All the inner leaf sheetrock would be suspended by isolated inner-leaf ceiling joists.

Still have not decided about the Green Glue just yet.... but I need to soon!... (whether I do or do not use the Green Glue or lead(?) has no bearing on the number of sheetrock layers)

After the between joist sheetrock with cleating is done, then comes the construction of replacement duct work for the above floor....
Will be using the Johns Manville SuperDuct board that I bought last week to construct the 5 ducts needed.

The between joist ducts will actually directly abut the insides of the between joist areas (essentially the between joist areas WILL be the ducts... the duct board will be fitted almost exactly to these dimensions).
The main duct will be assembled from the duct board and replace the section that bisects the studio, plus a short distance past it (to make mounting easier).

K

[Luftweg]

There can (and should) be a firm connection between the outer leaf wall and the outer leaf ceiling. The decoupling should occur between inner and outer leaves. There is no need to decouple one outer leaf assembly from another outer leaf assembly... Just as there is no need to decouple one inner leaf assembly from another inner leaf assembly. Remember, the goal is to prevent sound energy from following a structural path from the noisy place through the inner leaf along a firm connection to the outer leaf and into the quiet place.
--Keith

Although, a direct connection would not apply to where the layers of sheet rock meet at the corner intersections, right?
So, I connect a top plate directly to the above floor joists?

I don't think a 'direct' connection to the floor joists is the best, but rather a connection through a resilient material (in order to allow deflection of the joists under load, and not have floor pressures on the basement stud wall).
Should I use Celotex or something for that?

My idea for the outer-leaf wall was to:
1.) use isolation brackets on the top plates
2.) have the outer-leaf sheet rock extend up alongside the joist, but spaced about 1/2 inch away from the surface of the joist
3.) fill the gap with rock wool, firestop latex, and acoustic sealant (or just the Boss 816 which might serve both the firestop and acoustic purposes ?)

(see pic below)

Then again, I'm thinking that this seal might not hold under deflection of the floor joists.... hmmm....

Thanx for the help... I wish I could see what you are thinking in pictures...
Is there any way you could direct me to such?

Remember, I'm not floating any floor, but just using the concrete floor as both the inner and outer leaf.... yet the walls and ceiling will be true double-wall, double-leaf construction....

K

[sharward]

So, I connect a top plate directly to the above floor joists?

It depends on which top plate and which joist overhead. If it's an outer leaf top plate and an outer leaf ceiling joist, then yes.

Simply put, think of a box. Now think of a box inside that box that is "floating" inside of it -- no part of the inside box is touching the outside box. That is your ideal room-within-a-room.

Each side of each box is firmly connected, yet there is no connection between the inner box and the outer box.

Now, gravity being what it is, it's impossible to have a room float inside of another room without some decoupling devices. That's where floating floors, or, more ideally, floating rooms, come into play. Ideally, the entire room would float on elastomers (pucks of some kind) so that the bottom of the inner room doesn't have a firm connection with the bottom of the outer room.

If you're really doing individual inner room framing for walls and ceiling, as it seems from your illustrations that you are, then you don't have to worry about (and, in fact, should have) firm connections of the walls and celings.

This is one of the reason that doing independent framing (as you are) makes the design so much simpler. You don't need RC. You don't need RSIC clips. You don't need hangers. You probably don't need anti-sway braces. All you need to do is make sure there aren't any firm connections between inner leaf and outer leaf, and make sure there aren't any air leaks.

--Keith

[knightfly]

What you want is this; because your outer leaf can touch other parts of your outerleaf, and needs a continuous mass so there aren't weak spots. 2x lumber only equates to about 1" or less of gypsum in mass, so I'd extend your outer layers up to coincide with the beef between joists as shown in the re-do of your sketch.

Also, unless you need the iso there's no need to have the right half of the pic beefed up in the ceiling (ignore this comment if there's more sound iso required there) Steve

[Luftweg]

What you want is this; because your outer leaf can touch other parts of your outerleaf, and needs a continuous mass so there aren't weak spots. 2x lumber only equates to about 1" or less of gypsum in mass, so I'd extend your outer layers up to coincide with the beef between joists as shown in the re-do of your sketch.

Also, unless you need the iso there's no need to have the right half of the pic beefed up in the ceiling (ignore this comment if there's more sound iso required there) Steve

Actually, now that I see it, it seems absolutely right to extend the sheetrock to the floor....
One reason that there might be sheetrock on the joist space outside of the studio, is that my subfloor is plank, and not plywood...
Of course, I guess I could just seal the short spaces between the planks at that first between-joist area that is outside of the room....

One other concern of mine is: if the stud wall is rigidly mounted to the above floor joists, won't there be a deflection issue? that is, shouldn't the joists be allowed to deflect freely, AND couldn't any live load pressures supported by the outer-leaf stud wall work to loosen acoustic seals of the outer-leaf sheetrock?
Should this be addressed at the floor level (some sort of resilient material beneath the base plates)?.... or not at all?

thanx,
K

[knightfly]

One other concern of mine is: if the stud wall is rigidly mounted to the above floor joists, won't there be a deflection issue? that is, shouldn't the joists be allowed to deflect freely, AND couldn't any live load pressures supported by the outer-leaf stud wall work to loosen acoustic seals of the outer-leaf sheetrock?
Should this be addressed at the floor level (some sort of resilient material beneath the base plates)?.... or not at all?

No - if your outer frame doesn't let the floor joist sag in the middle, it's no big deal - that concern is only when you're placing extra, un-designed-for support under TRUSSES, which are calculated for each chord of the truss.

Only real concern here is, for isolation's sake, you don't hard-connect your inner leaf or its frame to your outer leaf or its frame... Steve

[Luftweg]

Some pics of the 'sister act'..... (the lines are the marks for where to put the screws)

I will have to say that the quality of the old joists seems above that of the new #2 (sruce-pine-fir) 2 x 8's that I sistered them with...
They are more likely # 1's...

For example (although I know this doesn't relate 'directly' to strength), when drilling screw holes in the new joist, the drill proceeded easily...
but the drill slowed and had a harder time going through the old joists...

They were screwed and glued (Titebond II).

In any case, when all the joists are sistered, I should no doubt be able to do 3 layers of 5/8 sheetrock! (I have consulted span tables that reflect that I will get at least a L/360 deflection... and certainly less deflection and more strength under the doubled joists).

At this point all joists, but two, are sistered.
Every joist will have been sistered completely; the span is 12 feet (about) and the sister joists are 14 feet long, so they completely rest on both the sill and center beam.
Plus, they have been 'pre-loaded' (with the aid of a hydraulic jack).
Next up is pulling down the between-joist heat ducts so I can sister those last 2 joists and finish blocking....

I will be installing some sort of 'temporary' heat ducting back.... this will probably be just some sort of foil and thin panel (read: cardboard) material to hold it up.
Ultimately, after the sheetrock is put up, I will be reconstructing all the above ducting with Johns Manville SuperDuct board, which should greatly reduce any sound that gets into the between-leaf ceiling space, and ultimately into the ducts (and thus into the above room).

K