existing buildings external wall question

bld · Post by **bld** » Sun Jan 25, 2004 5:34 pm

Hello, I posted earlier last year 2003 under a different user name (then re-registered because of silly excuse).

I'm attaching a design (unfinished) showing the basic corner controlroom design with the ISO booth in the upper right corner where I want to start first and continue as funds are available.

The building is about 250ft from nearest neighbors and is 24ft X 28ft w/8ft 9in ceiling height (which is 1/2" sheetrock no insulation with basic rafter pitch roof). There is some kind of 3/8in ply siding material with R13 wall insulation with 1/2" sheetrock finish and no internal wall/rooms.

I own the property and used to use it for a home ceramic, mold-making business I used to run out of it until Jan 2003, I did the internal sheetrocking/insulation for that purpose, there is a slight problem with some uneven ceiling joint (warped from not being taped/mudded for years) areas.

I don't plan on building floating floors and was wondering (besides question below before I thought of this question) do you run your walls all the way to the existing ceiling and how is isolation affected because of mutual ceiling between rooms and with the already shared concrete floor?

The questions concern when I build the ISO booth or any room is the sheetrock on the existing perimeter walls a problem STC wise, (I assume a few points lost) I have read many threads since coming to this site and keep refering to the SAE site but haven't quite determined if tearing off the sheetrock is the best way to go (I read recently someones thread about their basement ceiling sheetrock finish problem and deciding to remove it to add appropriate mass, airspace, insulation, RC and then re-sheetrocking it - mass). I also recently saw a thread regarding inside-out wall construction and thought that might be answering my question. I guess it isn't a big problem to tear off the sheetrock then I suppose add mass, insulate, seal (I think I'd rather lose a couple STC). Sorry for the question getting a little convoluted and I didn't really make notes from threads I read thinking it's pretty much all here but my searches haven't turned up anything specific without refering back to dozens of posts that take quite awhile to read back through. And I do feel I have a good grasp of alot of the sound proofing, isolation and acoustic treatment principles but of course there has to be something that seems to be unique without having someone right here looking at what I'm trying to describe.

I don't think I'm going to be recording hard rock/metal bands maybe acoustic rock or traditional flavors, so I'll go with some of the basic sound proofing methods then acoustic treatments. So...if anyone can give any tips on how to proceed I'd appreciate it. I do plan on wanting to start some construction within about a months time when I get my paid 1 week vacation from work. I know it's getting a little close and had intended to get this question posted weeeeks ago but continual searches made the time keep going on and on.

much appreciated,
bld

Post by **John Sayers** » Sun Jan 25, 2004 7:19 pm

mate - could you please draw how your skins works - it's hard to understand from your expanation.

cheers
john

bld · Post by **bld** » Mon Jan 26, 2004 3:43 am

Thankyou John for replying quickly, I hope this is what you may be looking for. Drawings of existing buildings perimeter walls. Is it best or worth it to tear off 1/2" sheetrock before building ISO room (or any rooms) walls?

Much appreciated,
Brian

knightfly · Post by **knightfly** » Wed Jan 28, 2004 3:22 pm

OK, now that we have drawings and some background, can you post your actual questions as clearly as possible? It would save me some much-needed time, thanks... Steve

bld · Post by **bld** » Thu Jan 29, 2004 11:45 am

Thankyou Steve for looking over my post I know you have been working alot of overtime hours so I do appreciate your time.

Below are 2 drawing samples (my trial version of smart draw just expired so now I have to fix that to be able to continue to make drawings to post).

I assume the existing buildings perimeter walls are considered a 2 leaf type wall however not hermetically sealed with whatever STC and the ceiling to roof (no insulation in attic) is another 2 leaf system.

My question per pic #1 is: (NOTE - pic says in ISO room 2 leaf walls next to perimeter walls, this is incorrect and shouldn't say that).
Do I take off the existing 1/2" sheetrock on perimeter walls, seal inside of ply siding, add mass by attaching layers of sheetrock between studs then replace insulation making a one leaf then build ISO room, control room and then live room with the one leaf per wall system?

OR

Per pic #2: Could I just seal existing perimeter wall and add additional layer of 1/2" sheetrock to add mass, then when I build ISO, Control and Live rooms the walls with air space next to existing building perimeter walls will be 2 leaf systems
and walls between studio rooms will be 1 leaf air space 1 leaf from room to room? I'd rather do it this way.

Also another issue is the shared existing ceiling, kinda up in the air about this one (pun

) getting up in attic sealing and insulating or building new ceilings for each room ???

Well I'm real late for work just wanted to get this to you and hope you can make sence of it.

Sincerely,
Brian

knightfly · Post by **knightfly** » Thu Jan 29, 2004 1:45 pm

I've seen the type of thin siding you're talking about - has just a bit more sound isolation than a cardboard box

- with your existing construction, your neighbors should have no problem hearing every note you play on a real piano in that room (been there) - as flimsy as your outer siding is, if you're willing to give up a bit more floor space you'd be almost as good just beefing up your existing inner wall surface (except I'd use two layers of 5/8" wallboard over the existing half, being careful to stagger seams and seal everything - you could then build separate free-standing rooms each with a multi-layer, single leaf wall and get relatively good room-to-room isolation. If you want better isolation you would need to float at least the live room's floor - choosing that floor would improve inside-to-outside isolation too, since that room will have the loudest sounds (drums, bass)

You may be able to add a layer to the existing ceiling and then build down with your second skin (the actual roof doesn't count very much, as it will be vented) - before I comment on the ceiling more, though, I need you to explain EXACTLY what your ceiling/roof construction is - stick-built or trusses or post and beam, size of framing members, spacing between framing members, spans without support, etc - you do NOT want to add material to a marginal frame unless you like pain and death... Steve

bld · Post by **bld** » Thu Jan 29, 2004 10:36 pm

Thankyou very much Steve. I will use this info to plan out some steps to take and especially after I take a look at the ceiling, I have a foggy idea of its construction and will take a look and report back. Most likely with a few other questions.

Once again thankyou.

Brian

bld · Post by **bld** » Wed Feb 04, 2004 11:57 pm

knightfly wrote:
You may be able to add a layer to the existing ceiling and then build down with your second skin (the actual roof doesn't count very much, as it will be vented) - before I comment on the ceiling more, though, I need you to explain EXACTLY what your ceiling/roof construction is - stick-built or trusses or post and beam, size of framing members, spacing between framing members, spans without support, etc - you do NOT want to add material to a marginal frame unless you like pain and death... Steve

Hello Steve, attached is a simple drawing (not to scale) looking at above the ceiling, what I believe is called the truss' or joists and rafters, they are constructed out of 2X4 lumber spaced 24" apart (along 28ft length), also lumber is connected by metal screen/plates as shown in the drawing. The truss' extend out over the perimeter walls (which are 2X4 studs spaced 16"OC) by about 24".
I hope this helps in determining the next step.

Thanks.
Brian

knightfly · Post by **knightfly** » Thu Feb 05, 2004 5:35 pm

OK, standard factory-built trusses - are you saying that the span from the left vertical support (wall) to the right vertical support is 28 feet, or are you saying that these trusses are across a narrower space that reaches 28 feet the "Z" axis (going away from you as you look at the drawing)?

I'll have to leave the wall questions for now, 'gators ain't gonna go away any time soon... Steve

bld · Post by **bld** » Thu Feb 05, 2004 11:47 pm

knightfly wrote:OK, standard factory-built trusses - are you saying that the span from the left vertical support (wall) to the right vertical support is 28 feet, or are you saying that these trusses are across a narrower space that reaches 28 feet the "Z" axis (going away from you as you look at the drawing)?

I'll have to leave the wall questions for now, 'gators ain't gonna go away any time soon... Steve

Thankyou Steve for taking a look.

I attached another drawing to help explain more, the span from left to right is actually 24 ft. There are 13 truss' spacing 24" O.C. running down (Z axis) the longer side of building walls 28 ft. (looks like my 28 ft noted measurement on drawing got shifted)
I also noted that the joists were also joined 2X4's with the metal screen a couple ft off center.
I'm sorry if I'm not diagraming or explaining well enough and hope it doesn't take too much of your time.

Will wait to see what you think.
Take care.
Brian

bld · Post by **bld** » Thu Feb 05, 2004 11:56 pm

Looks like last post didn't bump.
Brian

knightfly · Post by **knightfly** » Fri Feb 06, 2004 9:07 pm

OK, if your place was built with factory trusses they are (according to a local truss engineer I just got off the phone with) engineered for a minimum of 10 psf dead load on the horizontal chords (where your ceiling would go) - they would easily be able to take a layer of 1/2" sheet rock and two layers of 5/8" rock and still be under 10 psf. To be safe, I would at most use another layer of 1/2 and a layer of 5/8, sandwiching the 5/8 between the two layers of 1/2.

This would only be ONE of the required two leaves for a mass-spring-mass barrier - to get enough isolation to match your walls, you would need to build separate ceilings for each room with their joists bearing on the wall studs, hanging 2-3 layers of wallboard on Resilient Channel on those joists. Depending on your room dimensions, you might need to go as big as 2x8 for your inner ceiling joists - spans for 20/10 loading for #2 and better doug fir run only 10'8" for 2x6 joists on 24" centers - this increases to 13'6" for 2x8, and increases further to 16'6" for 2x8 doug fir, #2 and better, on 16" centers. For 10/5 loading, this increases to almost 24 feet but trust me, you don't want to go there. Each layer of rock runs around 2.2 psf for 1/2", 2.8 psf for 5/8. A second layer of 5/8 would put you over max loading with a long span.

Keeping this in mind, I'd recommend 2x8's on 16" centers for ceiling framing that bears on the new walls. I've done some concept drawings on one of the "sticky's" as to what needs to be isolated from what.

You mentioned enough ceiling height that you could probably get away with the 2x8's for inner ceiling support - assuming an air gap of 8.5" total between the inner and existing ceiling, and with a layer of 5/8 rock added to the existing ceiling, putting two layers of 5/8 on the inside Resilient channels, you would be looking at an STC of around 55-60, given proper construction.

That would keep up with any walls/doors your situation could deliver, so the ceilings wouldn't be the weak link.

I'll try to get to wall comments soon, please bump again if I happen to miss it... Steve

bld · Post by **bld** » Sat Feb 07, 2004 12:51 am

Well, OK, thankyou Steve for your quick and ready responses. My how it all escalates past my initial building plans

not that I didn't think that there was going to be a simple build room here build room there idea, I am pretty handy with tools and construction (remodeling other home projects, I totally gutted and rebuilt a little guest house on my property, bedroom, full bath, kitchen, wiring plumbing all internal walls mostly by myself though this time I'm sure I'll have to get alot more help for those new ceilings/structures.) but I digress.

Now I'm assuming that applying new sheetrock layers on existing ceiling (one leaf) and then applying more sheetrock layers on existing walls (one leaf, THEN when I build the individual rooms ISO, Control and Tracking I will be only applying sheetrock skins on inside of rooms walls(2nd leaf) with sheetrock applied to RC on new ceilings 2X8 joists (16" O.C. ) set over new room walls. Sorry if I'm repeating what you already laid out just trying to check my understandings so far so I can think about what steps to plan for, kinda already thinking to maybe make the control room first instead just have to round up more construction/material $$ than doing the ISO room first, but that's ok, I'd have to set up recording rig somewhere anyhow so might as well be in the Control room.
I'll leave it at that for now.
&
Your assistance is greatly appreciated.
Brian

knightfly · Post by **knightfly** » Sat Feb 07, 2004 1:46 am

Sounds like you got it - just to be sure, if you can do a sketch showing what you believe to be true, I'll let you know of any misunderstandings that may still exist... Steve

bld · Post by **bld** » Sat Feb 07, 2004 11:17 pm

Hello Steve, Thankyou for hanging in there helping me get my questions answered.
Here are a couple more drawings. Not to scale. (could almost frame a wall in how long it takes me to draw these up on the computer

it's _ good).
I know there are supposed to be gaps of R.C., chalking and so forth just gets kinda hard putting in all those details with a mouse.

Look forward to your reply.

Sincerely,
Brian