garage studio wall anchoring and ventilation

[groovemeister]

I am currently at the stage of construction where I need to decide on a ventilation system for the studio, and figure out how to anchor the inner leaf to the concrete. I have a 18' x 20' garage and we are finishing the exterior leaf. I have put durock board between the studs over the stucco (glued in and secured with a few screws). This is caulked and then filled with 3.5" of cotton fiber insulation. This is then covered with sheets of mass loaded vinyl and the seams taped. I am in the process of framing the inner leaf of the wall with consist of the studs filled with more insulation then closed-cell foam glued to 1/2" soundboard and then another layer of mass loaded vinyl followed by a sheet of 5/8" sheetrock. This is supported by neopreme square on the floor and mounted on RC-1 resilient channels. Seams on this leaf are caulked and sealed with metal tape. The ceiling has this same construction but hung on soundclips and hat channels covered with padding tape. I have put 1/2" particle board above the joists and insulation between the joists and also in the roof rafters. I am going to put carpeting and padding over a layer of MLV on the concrete floor. I decided against floating a floor for the timebeing for various reasons. One, being that the cost of this project is escalating, and second, I think that I can do it later on if necessary. Technically, I do not have a room within a room, because I did not want to go to the extra expense of putting another ceiling below the first set of joists. Hopefully what I am doing will be sufficient. After the length intro, here are my questions:

1. I need to get ventilation into the room and I need to decide on this before I seal up the ceiling and walls. I plan to get a mr. slim ac unit later on and am putting a 3" tube and the electrical connections now to facilitate this later on. The cost is about $3000 to do this, so it will probably have to wait until later on. However, getting fresh air into the room cannot wait. My electrician suggested a whole house fan mounted in the attic. I do not know if I can put ducts on this, or if this is different than a regular attic fan. I am concerned with the fan itself being too noisy and of the holes in the ceiling and roof defeating all the soundproofing that I am doing. Any suggestions would be appreciated. I have read most of the existing posts on this subject, but there does not seem to be any definitive answers.

2. I will need to anchor the interior leaf of the wall to the concrete, although it is on a layer of padding tape. I have heard mention of isolation bolt mechanisms (on Aurelex's acoustic 101) that have a rubber grommet so the bolt does not contact the sill plate, but I am having a very hard time finding these. Does anyone know of a source?

[sharward]

Welcome to the forum, Groovemeister!

Wow, you're really far along in your project, and from the look of the recipe, I can see why your costs have escalated. The experts here have weighed in on mass loaded vinyl (a.k.a. "MLV"), and the verdict is that it is a big waste of money since the same or better isolation can be achieved with less expensive materials. I'm sorry you didn't find this resource earlier so that we could have saved you that expense.

You really should check out my own project thread. Perhaps you already have -- but you especially need to look at pages 18-20, as I have been very active in planning for my own ventilation needs. Don't jump to any conclusions too fast, as you will see that I introduce ideas, then shoot them down the next day. I want you to learn from my errors and mistaken assumptions. For example, The mini-split ("Mr. Slim") A/C system will not provide any ventilation at all -- it will only condition the air that is trapped in the room! This will not pass code. You do not want to suffocate in pleasantly cooled carbon dioxide!

The ceiling has this same construction but hung on soundclips and hat channels

Stop! Hat Channel is terrible for isolation! Read this horror story!

Hopefully what I am doing will be sufficient.

Sufficient for what? It depends on so many factors. How loud are you going to be? How close are your neighbors? How noisy is the outside world and how quiet do you want it to be in your space? What's "sufficient" for one's needs will not be for someone else's.

My electrician suggested a whole house fan mounted in the attic.

Your electrician should stick to wiring. A whole house fan would be terrible for this application. They're noisy, require huge holes in your ceiling (24-30" in diameter), and do not supply any fresh air. Windows must be opened for whole house fans to function properly!

I do not know if I can put ducts on this, or if this is different than a regular attic fan.

Despite what you may see on the Internet (I just looked), attic fans and whole house fans are totally different. Whole house fans suck air out of the house and push it into the attic, where it then goes out the attic vents. Windows must be open in the house to equalize the pressure -- fresh air is sucked through the windows into the house. Attic fans, on the other hand, only circulate air inside the attic -- air is sucked into the attic from the outside and pushed out through the attic vents (or is it vice versa?).

I am concerned with the fan itself being too noisy and of the holes in the ceiling and roof defeating all the soundproofing that I am doing.

You are right to be concerned about those things. I think I talked you out of both of them.

I will need to anchor the interior leaf of the wall to the concrete, although it is on a layer of padding tape.

Padding tape?

I have heard mention of isolation bolt mechanisms (on Aurelex's acoustic 101) that have a rubber grommet so the bolt does not contact the sill plate, but I am having a very hard time finding these. Does anyone know of a source?

I know of one -- Mason Industries' Neoprene Partition Supports (model NPS). Unfortunately, Mason's Web site is stupid and even its own search engine points to pages that aren't available. So if you're willing, you can contact them, yell at them for having a Web site that sucks, and ask if they could mail or fax you the specs.

That should give you enough to ponder for a while!

--Keith

[the dreamer]

groovemeister wrote:
The ceiling has this same construction but hung on soundclips and hat channels
Sharward wrote:
Stop! Hat Channel is terrible for isolation! Read this horror story!

I just scanned the whole thing but as far as I know hadchannel has to be used together with some kind of rsic clips or similar which are basically hangers with rubberpads on which the had channel has contact with and hence decouples under load. (if loaded accordingly)
At least this is the system I know from Austria. Maybe you got different ones.
Florian

[sharward]

. . . hat channel has to be used together with some kind of rsic clips or similar which are basically hangers with rubberpads on which the had channel has contact with and hence decouples under load.

Ohhhhhh, yeahhhhh, thooooooose.... Sorry -- I just saw "hat channel" and freaked out.

[groovemeister]

Thanks for the info. Sorry to hear that the concensus on MLV, but I am still assuming that it will serve its purpose (although the 1500 sq. ft. was certainly a major expense compared to sheetrock).

I have found a ventilation system that I think will work. It is a Fanteck VHR 1404, which is a heat recovery ventilator. It is a relatively small unit (about 45 pounds) that I think that I can put in the attic. It is hung from chains and connects to flexible insulated ducts that take the stale air out and replace it with it with fresh air. They claim that it is a pretty quiet unit (although I do not know the exact noise specs). There are a total of 4 ducts connections on the unit - two to go to the studio room (one input and one exhaust) and two to connect to outside vents. From the manual I downloaded it looks like I would be able to branch these off into both the main room and the vocal booth. The interesting thing with this unit is that it helps to preserve the heated or cooled air being exhausted from the rooms if desired, so you would not waste all your airconditioning. It has a multi-function control unit that surface mounts in the room. I read that they normally recommend against attic installation for the following reasons:
1. The unit needs to be in a heated room to avoid freezing lines. (I live in Southern California where it will be rarely cold in the attic - which is completely insulated). However, it will get very hot up there.
2. Difficult to install. My contractor has put a small trap door in the attic so that we can get up there. although I am not clear yet on how we will get this trap door in the ceiling structure. We can get it up there, hang it, wire it, and then have some sort of tube for the condensation to go out of.
3. Maintainance will be difficult. If I put a ladder out of the attic I can get at this to change filters every 3 months without too much hassle.

The problem is that I really do not have another place to put this since I have a free standing garage, I am going to talk to a tech guy to see if I can get away with an attic install. Once I have proper ventilation, I can add a mini-split type AC unit later on (when I get some more $). I am convinced that breathing is a priority.

As far as the isolated bolt mechanisms, I am going to improvise by using some of my expensive MLV as an insulating sleeve around a standard lag bolt used for anchoring. I will just drill the hole in the sill plate slightly larger to fit this. I will also cut a "washer" to insulate the metal washer that goes under the nut. Hopefully this will have some decoupling effect.

[sharward]

I have found a ventilation system that I think will work. It is a Fanteck VHR 1404, which is a heat recovery ventilator. . .

Here's the spec sheet for the Fantech VHR 1404 (note the spelling -- Fantech, not Fanteck).

Very intriguing!! However, I'm not sure that you'll need or want to "recover any heat" in the room. My guess is that you'll always want to be "recovering coolness."

I'll definitely be giving this type of product a closer look for my project. Thanks for the tip!

(I live in Southern California where it will be rarely cold in the attic - which is completely insulated).

What do you mean here? The attic itself is insulated? Or the attic is full of insulation for the benefit of the space below?

However, it will get very hot up there.

You got that right -- I had a thermostat in my attic at the last house I was in, and I often saw it climb to over 140 degrees Fahrenheit up there.

My contractor has put a small trap door in the attic so that we can get up there. although I am not clear yet on how we will get this trap door in the ceiling structure.

Does this mean you have to beef up a ceiling that has a door in it already? Ouch.

The problem is that I really do not have another place to put this since I have a free standing garage, I am going to talk to a tech guy to see if I can get away with an attic install. Once I have proper ventilation, I can add a mini-split type AC unit later on (when I get some more $). I am convinced that breathing is a priority.

Yes, and so is meeting code -- without proper ventilation, you won't pass the inspections.

As far as the isolated bolt mechanisms, I am going to improvise by using some of my expensive MLV as an insulating sleeve around a standard lag bolt used for anchoring. I will just drill the hole in the sill plate slightly larger to fit this. I will also cut a "washer" to insulate the metal washer that goes under the nut. Hopefully this will have some decoupling effect.

I've seen references to this being done on this forum. However, be mindful that you're experimenting here, and it's impossible to know the outcome of those experiments, including whether not doing the experiment would have been better. Yes, it is conceivable that you might actually make things worse with your experiment (e.g., reducing the stiffness of the walls, which would allow them to resonate). Others here may disagree though. In my opinion, you should stick with construction techniques that are proven (i.e., tested in labs) to work.

[Dan Fitzpatrick]

Keith, you beat me to the punch there

I had already checked out Fantech's site a bit and was impressed. I'm planning to use them for my ventilation fan too.

I didn't see that unit before though. It DOES interest me, and maybe it should you too Keith, for those COLD Sacramento winter nights when you are pumping cold night air into your studio

The idea of having a space heater in my studio scares me ... maybe heat recovery system could help avoid that.

Groovemeister, i have the same problem as you with the fan maintenance issue. I haven't really solved it yet either. Do you have anywhere you can build a door to the attic space from outside the garage? it might depend on the design of the roof. in my case i could do that, but the door would be facing the street

this would be better than doing it from inside the studio because the sound iso wouldn't be affected as much. probably.

also you may want to use silencers to isolate the holes you're putting for the vents ... see my post on keith's thread if you haven't already http://www.johnlsayers.com/phpBB2/viewt ... 0147#30147

one more thing ... you ARE getting the fresh air from outside, right, not from inside the attic

d

[the dreamer]

Hi,
http://www.heliosfans.co.uk/katalog/pdf ... uk_kwl.pdf
The Helios KWL 350 is the unit I have for my CR. I got a real good deal on it. It has a build in heat exchange system (-10 to-20 in winter around here) and an electrical heater. Very cost efficient. Let's say the exhaust air has 21° and depending on the outside temperature I get return air with 16° (if it is really really cold) up to 19° and the build-in heater makes up for the rest to get the 21° again. That's a must have around here as electrical power isn't that cheap than in the states.

[knightfly]

Groove, you seem to be getting good response about the ventilation part; but what concerns me is that no one has mentioned the fact that

Durock/stucco = mass
3.5” cotton wool = air
MLV = mass
Studs + insulation = air
Closed cell foam, MLV, soundboard and gypsum = expensive but “mass-challenged” mass

All of which = a 3-leaf barrier, which will HURT the low frequency TL of your walls.

Also, your ceiling description sounds like it won't come up to the TL of your walls - any possibility of your posting a sketch of what you're doing, or are you at a point where you don't care?

I can understand things getting expensive, with two layers of MLV involved. On the plus side, the stuff reportedly has good damping characteristics... Steve

[sharward]

Heh - sorry for missing that, Steve -- I guess I was (and am) in such "ventilation" mode that I zeroed in on that, and of course I couldn't resist the low-hanging MLV fruit!