Bid on a house for a studio

[RICK FITZPATRICK]

Hello FS. First off, ongrats on the house. After looking at the pics of your studio construction, I saw some things that seemed...well, at least to my mind, a little wierd from an isolation point of view.

I don't know who planned this, or if you are doing the plan and someone else is doing the work or what, but there are some things I don't quite understand. Maybe you can clarify them. If I am correct, I hope you haven't coverd these up yet.
Please don't take offence to my observations. I'm only offering comments that may help you prevent mistakes and insight to some potential problems that you may fix, although, I could be wrong, considering it is awfully difficult to ascertain your actual conditions from a few pictures, not to mention the whole scope of your construction detailing.

Well I put up sheet rock on the existing extirior walls. Two sheets of half inch with green glue in between. I did three layers in places.

First off ,when you install the drywall on the interior face of the new construction, you will have created a THREE LEAF SYSTEM! What you have done is WEAKEND the transmission loss potential. It is a proven fact that a THREE LEAF system is inferior to a TWO leaf system. Although, without knowing the conditions of the exterior leaf, and if each stud cavity is being vented to the outside, I could be wrong. However, IF, you haven't vented these cavities, you indeed have created a three leaf system Thats not to say you won't reach your transmission loss goal. Its just saying it could be better, had you understood this principle in the first place.

Second, I see windows framed within the interior shell framing. How are you planning on keeping the TL of the windows at the same TL rating of the
rest of the wall assembly? Unless you are using VERY THICK glass, like 3/4" or so, I believe you have built in a VERY WEAK LINK in the overall scheme, which in terms of $$$$, means you have negated all the work and money spent on the rest of the shell. Again, without knowing your TL goal, I could be spitting in the wind. Regardless, I believe my assessment is still correct.

Third, in one of the pictures, it appears there are some spacer cleats fastened to the drywall/framing of the exterior shell, which from a common sense point of view, means that these spacers are TOUCHING the interior shell framing, no? If I am correct, then these connections provide a flanking path for structural transmission DIRECTLY to the exterior shell, which again, will negate all attempts at isolating the interior shell from the exterior shell. Unless there is some kind of "decoupling" agent between the interior framing and the cleat which is not visible in the pics. This concept is so important to isolating an interior room within a room, pro studio builders go to great lengths detailing EVERY connection to the outside world so the WHOLE room is "decoupled" from the exterior shell. Every single component in the "system" needs to be addressed, from HVAC ducts/registers, to door jamb/thresholds to "WALL SWAY" decouplers, not to mention electrical conduits, pipes, and many other "connections", which now brings up the daddy of them all. The floor.


Modern Home studio construction school of thought maintains that MOST home studios do not need a "floating room", as this type of construction is not only HIGHLY difficult to implement correctly, it is also very expensive to do correctly. And without really knowing your TL goal(you do have a goal don't you?) my observations may not have any merit. However, there is something I see that, given a certain TL goal, may also contribute to "weakening" the rest of the "room within a room" construction TL potential. Your slab is also a DIRECT vibration transmission flanking path to the exterior shell. To overcome this problem, the usual method is ISOLATING the interior slab from the exterior shell slab/footing. Not only that, but once you "decouple" the interior slab, usually by cutting the slab with a diamond saw, then, because the weight of the whole "room within a room" structure is carried by a thin floor slab (which from my own experience may fracture the slab), which from a permit point of view, demands a new "footing" must be poured to bear this weight. I know this comment will do you little good at this point, but it MAY help others who need extreme Transmission Loss construction, and may not understand the problems and inherent "permit" difficulties, not to mention potential "insurance voiding" should this type of construction occur WITHOUT going through the permit process. Not to mention possible fines and legal consequences, INCLUDING DEMOLITION! For those of you in this group who intend on this depth of construction, I HIGHLY advise reading this thread in its ENTIRETY.

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=2921

Anyway, take my comments with a grain of salt at this point. They are only intended for others to consider should they be in the PLANNING stage of their future projects. Hope this helps them somewhat, although there are MANY other considerations. BTW, what is your plan on the ceiling and HVAC?
fitZ
fitZ

 

[Freudian Slip]

Hey Rick,

I'll try to answer some of your questions.

I'll start off by saying that for now this house must remain a liquid asset and the bulk of the money is being spent on the upper two floors.

My TL goal is to simply make it tolerable for my neighbors.

My choice to install the multiple layers of drywall on the inside of the extirior wall was driven by the fact that the inner wall framing and drywall is contracted out. I may add additional layers on the inside wall if need be, but for now this is what I could do and allow the inner walls as to be finished as normal construction.

I am in discussion with the contractor on the cleats. Some of them are temporary because not all the walls are connected yet.
Some walls are going to be incorperated into the existing structure because of budget issues and that's just he way it has to be. Those walls will all be inside walls though.

The windows are going to be drywall wrapped for now. I plan to build caps from plywood and multiple layers of drywall to be that will be suspended from the inner wall and gaketed to the wall with thick felt. It will leave about a ten inch air space between the cap and the window.

The ceiling is going to be dropped to 10 ft 6 inches due to cost. Any taller and there has to be approved enginiering and fireblocking and the price shoots up alot. I did run the drywall up to the floor joists on the outside wall to try and compensate for loss out the ceiling.

As far as HVAC goes. The main unit is located on the far side of the house.
All of the outlets run all the way back to the main unit and are not shared lines. I do not think it will be a major as far as transmission between the rooms and I see it as no problem at all for transmission loss to the outside. most of the ducting is on the otherside of a shear wall with at least 12 inches of cement and alot of earth between them and the neighbors.

On nice thing is that there is no nieghbor and never will be on one side of the house.

Anyways I just got back from working on the upstairs of the house so it's dinner time.

The fact of matter is that there is alot of stuff that will have to be done later.
I am going to try like hell to get rid of those cleats though!! That's my biggest concern.

I will take venting the outer wall cavity into consideration. I will likely wait until I give it a test run with the drums and bass.


Later.

F.S.

P.S. You haven't even seen the french doors

*** Edit***** Missed it I'm tired and burnt. The inner wall is not going to the ceiling and will release into the underground area of the basement. My bigger concern will be isolating the control room from the live room and drum room. I will have all the time in the world to do that. the control room will have a dual wall with no coupleing except the shear wall on the end. I am hoping that the long run on the hvac system back to the unit and then back out to the control room will be enough to make that dealable. the venting will be at a great distance from the monitoring position too...

 

[Freudian Slip]

Got the ceiling joists installed and checked the with the buider about removing the cleats. He said that is I was willing to sign off on it that he had no issues. He also shook the framing and said that it shouldn't be any problem at all. I do however have to wait until after the building inspector has come and gone.

So I was very happy to hear that!

F.S.

 

[gullfo]

looks like a nice space! i have to agree with fitz - adding the inside drywall probably cost you 10db of low frequency isolation. now if you have put the drywall between the studs, you could have gotten another 5-6db plus whatever you get from the inner room. in any event it is what it is... the French doors actually should be OK if they're good quality exterior grade doors.

on the height - you might have been able to angle the ceiling up on the edges to increase the room height for most of the room without changing the fire stop requirements... that said, i would have thought the cost of materials would be the most cost versus some additional fire stopping... about 30% more materials...

on the ceiling - are the walls secured with isolation clips? the ceiling with isolation clips? just shaking it isn't the same as when you have many thousands of pounds of heavy drywall layers hanging over your head plus any earthquake regulations...

 

[Freudian Slip]

looks like a nice space! i have to agree with fitz - adding the inside drywall probably cost you 10db of low frequency isolation. now if you have put the drywall between the studs, you could have gotten another 5-6db plus whatever you get from the inner room. in any event it is what it is... the French doors actually should be OK if they're good quality exterior grade doors.

on the height - you might have been able to angle the ceiling up on the edges to increase the room height for most of the room without changing the fire stop requirements... that said, i would have thought the cost of materials would be the most cost versus some additional fire stopping... about 30% more materials...

on the ceiling - are the walls secured with isolation clips? the ceiling with isolation clips? just shaking it isn't the same as when you have many thousands of pounds of heavy drywall layers hanging over your head plus any earthquake regulations...

Well as I understand it besides the fire stopping, the fact that we would have to buy longer studs and cut them down plus having to have it get an engineering stamp of approval would have cost me up to 2 to 3k more. That's not alot but with everything else we have to do on the house we are already way over what we planned on spending. If I did pay the extra I would get about a foot of extra hieght out of it.

The ceiling is the real week point as far as tramsmission loss is concerned.
The joists are toe nailed on the ends and they have hangers from the floor joists every 8 feet or so. It's certainly not going anywhere but will be passing quite a bit of sound to the upstairs and some to the outside. I will just have to see how bad it is on the outside. I will have access to the hangers and could rubber isolate them one at a time after construction if need be.

The fench doors are exterior metal doors. Cheapo stanley type things. I may install another set of doors (to make double doors) down the road.
If there is bad enough leakage at the doors I might put one sheet of drywall on the inside of them.


Dave