FINISHED IN 2020! Sharward's Partial Garage Conversion

[andyroo]

Several of us are on the verge of installing fresh air ventilation systems and silencers, so hopefully this area will abe more effectively covered once we have them up and running with all the requisite pictures to go with them.

I agree. There is far too little information on how to do it right here. I've been guessing most of my way out of doing mine.

Congratulations on the mini-split. I just finished mine, and it is a great feeling.

[sharward]

Hey andyroo! Almost DT time! Post pictures of your mini split system! We need a Mini Split Hall of Fame!

[studio_drums]

Keith,

What are you going to put in the gap between slabs?

Does Rod recommend anything?

[sharward]

I don't have anything but air around my new slab, but I did cover the gap with a premium grade (Shaw brand) three-in-one laminate floor underlayment material that acts as a capilary break under the soleplates of my inner leaf wall frames. I used two beads of GE Silicone II caulk under the frames and along the outer foundation as a seal, plus I used a staple gun to hold the material up along the outer leaf so as to keep gravity from eventually peeling the material away from the caulk. The material has anti-fungal properties too. It's an unorthodox method, I'm sure, and it wasn't cheap, but I felt better about that than I would have using ordinary plastic sheeting. I took pictures - they're buried in this thread somewhere...

In other news... I didn't report this before, but I had another snafu with the mini split: again it lost its cooling luster, so I again feared a leak in the system somewhere, bracing for the worst. Ends up it was just another bad connection on one of the refrigerant line flare connections behind the indoor unit. My tech tightened it up and tested both connections for leaks very thoroughly this time.

Whereas before the fix the unit was pumping air through that was about 10°F cooler than what was being sucked in, after the fix it is about 28°F cooler!

Moral of the story: make the tech follow the instruction manual to the letter, and make that a part of your agreement ahead of time! If he had followed the documented procedures by tightening the connections to the specified torque and used the liquid soapy stuff to look for leaks on day one, it would have saved him two return trips and me a lot of worry!

I just returned from four concerts over six days -- all three California Dream Theater / Redemption shows (San Diego, Hollywood, and Berkeley), plus Symphony X in San Francisco. What an(other) awesome experience. I won't bore you with details, but suffice it to say that I'm pumped with inspiration and motivation to get this damned room finished so I can play!

[sharward]

I was pretty lazy this weekend... It seems the energy I expended during my trip and concerts caught up with me. But I did drag myself to Home De(s)pot to purchase some stuff with which I'll be making my fresh air ventilation silencers.

I've been testing the mini split every few days, and it's been running great with 25°F+ degree differentials. I really think there are no more leaks!

Hopefully I'll have something worthwhile to report in the next week or two.

--Keith

[studio_drums]

Hey Keith,

I'm waiting for more information on how you're going to do your ductwork.

I'm really worried about compromising the integrity of my room.

[sharward]

I wish I had something to report. Unfortunately, all I have to report is that I have nothing to report. We're in the midst of a big upgrade at work, so I couldn't work on my studio this weekend at all as I had hoped/planned. Hopefully I'll be able to accomplish something next weekend.

Well, truth be told, I did cut some OSB and timber last weekend for a few hours -- pieces of what will become my silencers -- but there's nothing photogenic yet.

--Keith

[sharward]

OK, finally -- something to report, with photos!

I'm done with one of my silencers and I'm working on my second one now. It will be a virtual twin of the first.

I hope this design will work -- I'm always one to jump on people who "guess" at solutions, but I have to admit that's what I'm doing in this case! I think and hope that I'm "overkilling" in a lot of ways that any shortcomings with this design will be compensated for and that this won't be a major "weak link" in my overall design...

So, to recap a bit -- I had originally intended to have four very large (about 8' x 2' x 1') silencer boxes: two on the inner leaf and two on the outer leaf, two for incoming fresh air and two for outgoing exhaust air. These silencers would have looked like soffits along the ceiling in the back and front of the room.

I decided along the way that would be too much work for me... ...and I've seen some examples and read some accounts of people building their silencers into their ceilings between ceiling joists. I decided to give that a shot.

I also decided that I would try to get away with silencers only on my inner leaf. Since the ducting will be running into my attic, I figure that if I need silencers added to the outer leaf, I can build them later inside the attic where the ducting comes in from the studio. This would not be ideal, but I can do it if I must. The prospect of building them inside the attic is daunting, as getting the materials fed up into the attic space and assembled there (as I expect they would be too heavy to attempt to push up, especially working solo as I usually do) is not something I look forward to, so I am cautiously optimistic that it won't be necessary...

I started out with a piece of 2' x 4' OSB, plus two sections of of 4' x 16" x 5/8" drywall screwed to it, with a fair amount of Green Glue sandwiched between each layer (OSB-GG-DW-GG-DW).



I then took a couple of 9" x nearly 4' long strips of OSB and screwed them to some 4 foot long 2x4s, using Green Glue in the hopes of minimizing sustained resonance.



I had to get "jiggy" with the jigsaw for this piece...



I cut a 9" round hole into the outer leaf ceiling, fed through an 8" wide insulated flex duct, attached it to a very nice galvanized ducting elbow connector that smoothly transitions an 8" round duct to a rectangle measuring 12" x 3 1/4", using metallic duct tape along the way:



Here's the silencer box sealed on the inside with acoustic sealant, using a putty knife to ensure a good "bite" to the OSB. This box is designed to hopefully "keep up" with the mass and isolation properties of the rest of the build.



The box is nearly 4 feet long and measures about 9" high and about 13 1/2" wide.

With the inner ceiling and the outer ceiling and the top of the box in between, that's three leaves, folks! ...But, as I understand it, it's pretty much impossible to build a silencer without creeping into three-leaf territory -- we just try to minimize it where we can and make up for it as best we can along the way, right?

I then stuffed two batts of 3" thick Thermafiber SAFB (2.5#psf) into the top of the box, then used some plastic sheeting left over from my concrete pour to cover it up. This ensures that the fibers from the insulation won't break loose, and I think it will also provide a smooth surface for air to flow by, thereby reducing friction / static pressure. I also attached a register box that starts out with the same size opening as the piece on the other end (12" x 3 1/4"), which then makes a smooth elbow down to a generous 12" x 8" register opening.



This side view is probably easier to follow -- you can see where the duct enters the outer leaf ceiling on the far right.



I'm more than halfway through the second one now, as many of the pieces I had to cut for the first were cut at the same time as the second.

Note that the fresh air ventilation system I have has 6" ports, so I'll need to reduce the 8" flex duct down to 6", probably as close as possible to the unit. The distance from unit to studio will be very close (laundry room adjacent to studio). I will try to keep the ducts as straight as possible with bends that sweep as gently as possible.

My hope is that the 3 feet or so of 6" thick Thermafiber SAFB insulation that the sound will pass below prior to exiting the room will absorb at least some/most of the sound before it arrives at the penetration!

I'm almost afraid to ask, but any feedback from the pros would be appreciated before I paint myself too tightly into this corner!

Thanks all,

--Keith

[johnz]

i'm no expert, but my first impression is that you might want tar paper lining the inside of the osb box. i remember something about this from paul's studio build, i think it was a suggestion from eric. something about moisture control.

also, wouldn't fabric work better than the PE film you're using? the low freq waves will still get to the rockwool to be absorbed, but high ones might just reflect off the plastic and into(or out of) your studio.

what you've got looks good, i hope someone with more expertise chimes in to help a bit. silencer boxes are a gray area round these forums. I was disappointed that rod didn't include anything about them in his book.

[Dan Fitzpatrick]

Hi Keith,

Nice to see your progress. I know it's hot these days in Sactown.

I also think the plastic is an odd choice. Isn't the rule that you want to use fabric you can easily blow through to cover up acoustic treatments?

I used grey lanscaping cloth from home depot. It might be better to use something like that.

It's very tough stuff, easy to use, you can staple it and it won't tear away. It's fine enough mesh to stop fibers (i think so anyway) but you can blow air right through it.

I think i have a picture of the label somewhere in my thread.

Dan

[rod gervais]

Use John Mansville Duct Liner - it has a black polymer coating and that was a part of the assembly when they tested it acoustically -

The plastic is a bad move- and will increase air noise.......

Rod

[sharward]

OK, cool -- thanks for the input guys. I'll see if I can get my hands on the duct liner.

[sharward]

By the way, I just wanted to say I had figured on using the plastic since I assumed low end TL was my biggest concern and that I might be able to afford a bit of high end TL inferiority in favor of using a material I had on hand and that was sure to not deteriorate over time... I must confess that I'm getting a bit of Why The Hell Am I Not Done With This Damned Thing fever and the temptation to Just Get The Damned Thing Built Already is calling out to me!

But, I'm not fighting the advice I'm being given, so on I go with my quest to acquire The Proper Materials For the Job At Hand!

Thanks to all who have responded. Dan, it's good to see you're still tuned in!

Now then... Which of these Johns Manville products is the one I need to get my hands on, and in what thickness?

• New! LinaTex™ - Textile Fiber Duct Liner
• Linacoustic RC™ - Fiberglass Duct Liner w/ reinforced coating system
• Permacote® Linacoustic® R-300 - Rigid Fiber Glass Plenum Liner Board
• Permacote® Linacoustic® HP - Fiber Glass Duct Liner

...and can anyone recommend an online source for a small quantity?

And also, to clarify -- I'll be covering the 6" of Thermafiber that I have stuffed at the top of the silencer boxes with this stuff -- right? And... Should I also line the sides and bottom of the boxes with it as well?

In the event that the Johns Manville product is not available to me locally or online in a small quantity, is there an equivalent/competitive product I might be able to substitute?

--Keith

[joey]

keith your doing good dont rush it now. it will be worth it in the end mate.

[rod gervais]

Now then... Which of these Johns Manville products is the one I need to get my hands on, and in what thickness?

• New! LinaTex™ - Textile Fiber Duct Liner
• Linacoustic RC™ - Fiberglass Duct Liner w/ reinforced coating system
• Permacote® Linacoustic® R-300 - Rigid Fiber Glass Plenum Liner Board
• Permacote® Linacoustic® HP - Fiber Glass Duct Liner

...and can anyone recommend an online source for a small quantity?

Any of the last 3 should be fine - I am not familiar ith the first.

1 1/2" thick is hat I ecommend.........

if you have an HVAC contractor - that is a sure bet - just buy it through him..........

if not - CALL THE MANUFACTURER.......... tell them your story and ask them here you should go -

you would be surprised - JM even has some distrobutors that they will let you buy from even though you aren't in the biz........

And also, to clarify -- I'll be covering the 6" of Thermafiber that I have stuffed at the top of the silencer boxes with this stuff -- right? And... Should I also line the sides and bottom of the boxes with it as well?

I would remove what you have and substitute this for it - unless you really went overboard with your sizing - your clear space inside per linear foot of run shuld be a minimum of double your duct size feeding it........

In the event that the Johns Manville product is not available to me locally or online in a small quantity, is there an equivalent/competitive product I might be able to substitute?

Always preparing for the worse............ oh well..........

Any duct liner from any manufacturer - as long as it is black faced polymer lined - should be sufficient................ they are really all fairly comparable in that respect..............

rOD