drywall between ceiling joists

[DrummerMan]

This is not for me, but for a friend.

He lives on the bottom floor of a two story building. Upstairs are some rowdy kids (like, 3 year olds). The ceiling in his living room is just joists with the floor boards nailed down on top. No subfloor. nothing. When someone is walking upstairs it it LOUD, like louder than if they were walking next to you. When the kids upstairs are jumping around, it is pretty unbearable.

His landlord has agreed to 1) put padding and carpeting down upstairs. 2) Is buying enough sheetrock (drywall, gyp board, etc.) so that my friend (probably with my help) can put 2 layers up on his ceiling. The room is pretty short already, and my friend really doesn't want to lose the 6 inches by attaching the sheetrock to the bottom of the joists, so he's going with putting the sheetrock right up against the floorboards, between the joists, essentially adding mass to that one existing layer. Since I'd seen this process in the Rod Gervais book, I gave my support to this endeavor.

There isn't going to be Green Glue involved. There's just not the $$ for it. Let's skip right past the fact of what the landlord is supposed to do and what my friends rights are and what the situation should be, and go right ahead to the reality of dealing with the situation that we've got to deal with.

So, finally to the questions...

1) In Rod's book (p.66 for those reading along), it suggests holding the board temporarily in place with finishing nails while you caulk around the edges. A) Am I supposed to nail kind of sideways at a slight angle into the joists to hold up the boards (like it kind of looks like in the pics)? or should I actually nail right up into the floor above? and B)it says "temporarily" but it doesn't say when and/or if to remove the nails and the finished pic on the next page still shows what I assume to be nails holding the boards in place.

2) The book suggests replacing, at the end, whatever cross bracing (bridging) you removed before starting. If there wasn't any bridging to begin with, does there need to be some added now that there's sheetrock up in there? My instinct says yes, but what the hell do I know...


I know I should probably post this over in the Sayers forum, but I'm hoping someone who's dealt with this issue around here might have some thoughts.

I thank you, and so does my friend.

[losthighway]

I'm doing this exact thing (except with green glue) in the next couple months as my studio expands into my home. I can tell you that adding bracing afterwards would be a good idea to increase your structural integrity. All of that drywall adds a lot of load to the ceiling. I can also recommend you add insulation over the drywall.

As far as the fastening process, I am still uncertain myself. I have talked to some people about nailing, or screwing straight up in to the floor boards (measuring of course for the proper screw length so as not to go through the floor up stairs.

In the book he uses a little more abstract language discussing "cleats".

Maybe someone who has done this will sound off on that detail. But in the mean time the overall project seems very practical to me, and has been backed up by several more experienced board members.

I just keep thinking: how much dry wall am I gonna end up cutting (a ton), and how exhausted are my arms gonna get putting it up (extremely)?

[DrummerMan]

I just keep thinking: how much dry wall am I gonna end up cutting (a ton), and how exhausted are my arms gonna get putting it up (extremely)?

"Extremely" is right.

A couple months ago I was putting sheetrock on the ceiling of my actual studio build and MAN, that SUUUUCKED!! I had one other person helping me and the ceiling was only 7' tall to begin with but that shit was tiring...

The only possible saving grace of the between studs thing is that the boards are not as wide. Anyway, I'd still try to make a 3 person job. 2 to hold it up, 1 to nail/screw it in.


and when you say this:

I can also recommend you add insulation over the drywall.

do you mean between the drywall and the floor, or on the outside, exposed to the room? and what's your rationale for that, if you don't mind me asking?


Also, I think I missed the part about cleats. Do you remember offhand what page that's on?


Thanks for your input.

[losthighway]

Okay 'cleats' I think someone else on here used that term, and it stuck with me cause I didn't understand it..... maybe that's what Aussies call nails (ha!).

But revisiting the Gervais diagrams (page 67-73) there are some terms I'm not too solid on. (Probably cause I am no carpenter, but instead someone who runs at things, screaming with power tools in hand and hope for the best.)

He indicated that you should install the extra drywall with a 3/8" backing rod as opposed to screwing it into the floor above. Then you would add caulk (without laughing when saying that aloud to your friend helping you). My problem is I don't know what a 3/8" backing rod is .

As for the insulation question, you can see many of the diagrams include insulation (below the newly added drywall in the joists). That will add to your absorption/isolation. If you choose not to finish your ceiling with drywall (sure the hat channel would be sweet, but if your already working with limited space a few inches might be too many) you could leave the insulation exposed for partially helpful broadband absorption. This may of course make the room too dead. I was going to try it and see, before I went back to the store for another twenty sheets of drywall.

It does seem that a short ceiling that is a little dead seems to cause less problems than a short ceiling that is really echoey.

edit/ps Oh Google is smarter than me. Backing rod is just a roll of foam tube stuff, works like a gasket. Makes sense for isolation. I suppose in the picture the only thing holding the drywall up is the 1/3" ledger board which would appear to be screwed into the side of the joists.

Again, experts please chime in and lead these blind fools, for we are lost in lumber-land.

[DrummerMan]

Yeah, the backer rod is supposed to go around the edges of the sheetrock, in the 1/4" gap you hopefully should've left around, not between the layers. Then caulk over that.


I see what you're saying about the insulation inside. I think that's more for affecting the internal acoustic sound than transmission from the outside and since this situation for my friend is simply a living space and not a studio at all, I think he'd rather have the clean lines of just drywall than any exposed fabric.

I am no carpenter, but instead someone who runs at things, screaming with power tools in hand and hope for the best.

This shit cracked me up!

I definitely started out as the same type of person. If I wasn't, I probably never would've done some of the crazy, yet really rewarding projects I've done in my life. Luckily, this approach teaches "experience through mistakes" really well, too. Sound insulation definitely requires some proper forethought, but I really like how easy Mr.Gervais makes it for the lay person to get at least most of what he's talking about.

[JamesHE]

I suppose in the picture the only thing holding the drywall up is the 1/3" ledger board which would appear to be screwed into the side of the joists.

.

This is a "cleat"

Paneling and cabinets are often held in place with a "French cleat" This is is a system that involves interlocking cleats. So often people will, like in this situation, call anyting that holds something up 'while the glue dries' a "cleat"


I am a carpenter, and I still go running at things with power tools. except sometimes i get paid for it. (or used to before the market took a crap)

[losthighway]

Cool. I learned something new. I get the feeling you could leave these in permanently if the only other thing that's holding the drywall up is the pressure from compressing the backing rod and some caulk (try to say it out loud without giggling).

My question to you, since you seem to know this stuff is: would you put this ledger board cleat in first, and then diagonally slide the drywall up into place between the joists, or would you have to have someone hold the drywall up and then press in the ledger board snug against it, then screw it in?

But then I suppose if you do that you will have blocked off the little space where your backing rod is exposed for caulking.

Shit, building is hard. I'm glad I'm talking to you guys before I get started.

[DrummerMan]

My question to you, since you seem to know this stuff is: would you put this ledger board cleat in first, and then diagonally slide the drywall up into place between the joists, or would you have to have someone hold the drywall up and then press in the ledger board snug against it, then screw it in?

While in theory this may seem like a flawless, or at least doable, plan, I'd advise against it.

Murphy's law dictates:
-It won't go as smoothly as you think.
-You will think you measured the right depth between the current ceiling and the cleat, but you won't have.
-Other things that I'm not thinking of will come in to play screwing you up.


When I was putting up drywall on my ceiling a couple months back, I had the bright idea that if I put the wall sheets up first, leaving enough room for the depth of the sheetrock + 1/4" for backer rod/caulk, I could just lift the sheet on one side, jam it into the slot on that side, which would hold it in place while I lifted the other side, and with a slight bend, just POP it right into place on the other side (the room is less than 8' wide)! allowing me to then screw it in to my hearts desire without a care in the world...

The most embarrassing part was when the piece of sheetrock, which was slathered in Green Glue on top, flipped over on top of me, covering me in icky, gooey, green shit that doesn't come off really easily . I was finally able to get another person to help with the ceiling, but it really should've been three people, like I said before: 2 to hold the stuff up, 1 to screw it in.


So yeah, hold up the sheetrock first and secure it to the ceiling, then put it whatever supports you'll need. That'll also ensure a snug, secure fit.[/list]

[losthighway]

What I'm thinking is that if I screw the drywall up into the floorboard it will be a lot more coupled than if it is just resting against the cleat. I would imagine it could transmit a lot less energy through the floor that way. This wouldn't prevent me from screwing it in with a couple screws, and then taking them out after installing the cleat.

I wonder if I'm going to have to pay my buddies this time. The ceiling is like 360 square feet. Last time they got beer and pizza, but that ceiling was only 180 square feet, and we weren't putting the stuff between the joists, so there was much less cutting.

[DrummerMan]

One way to offset the work you're asking of your buddies would be to do as much of the cutting by yourself beforehand as possible. Especially if you have consistently wide joists, that part should be easy enough.

[JWL]

His landlord has agreed to 1) put padding and carpeting down upstairs. 2) Is buying enough sheetrock (drywall, gyp board, etc.) so that my friend (probably with my help) can put 2 layers up on his ceiling. The room is pretty short already, and my friend really doesn't want to lose the 6 inches by attaching the sheetrock to the bottom of the joists, so he's going with putting the sheetrock right up against the floorboards, between the joists, essentially adding mass to that one existing layer. Since I'd seen this process in the Rod Gervais book, I gave my support to this endeavor.

I understand your logic here. What you describe will definitely help. However, the existing ceiling is a 1-leaf system (floorboards and joists are it... only leaf). By beefing it up, you will add mass which lowers resonance, but it is still a one-leaf setup.

I understand about the ceiling height, but the best approach here to stop as much sound as possible would be to stuff the ceiling with insulation, install a resilient channel, and hang drywall from that. Even 1 layer this way would probably outperform 2 layers in the one-leaf system.

[Waltz Mastering]

I agree with JWL. But if your friend has talked himself into doing sheet rock between the joist, why not use sheet rock screws instead of nails? I think you would find the way JWL described as being way more effective for sound deadening and a lot easier to do.

TW

[losthighway]

The Gervais book shows a design for doing both of those things together. I guess the ultimate question is: how far does your ceiling drop using a resilient channel- RC2 clips + drywall. If it is less than 2 inches I could imagine not caring. Beyond that, if you have a smaller space that is just too much shrinkage.

[rhythm ranch]

Whether one leaf or two, between the joists or across them, DO NOT try to hold up drywall yourself. That shit is too heavy even with help.

Slap together a couple of these:



Just make the "leg" a little longer than the distance from the face of the drywall to the floor. You just wedge it between the floor and drywall.

[stuntbutt]

I guess the ultimate question is: how far does your ceiling drop using a resilient channel- RC2 clips + drywall. If it is less than 2 inches I could imagine not caring.

RC1 and RC2 aren't used with clips. They are channel and attach directly to the underside of the joists. You lose a half inch from the channel and the thickness of your drywall.

If the foot-fall noise is unbearable now I would go the extra mile and add a layer or two of drywall between the joists up against the subfloor and do a layer on resilient under the joists. The cavity should be filled with fiberglass.

This is only if, and it's a big IF, you are sure that the ceiling joists can support the weight. I would only feel comfortable if I had an engineer's stamp on that.