New Construction in a 2 car garage. Need advice desperately!

6' 5 1/2". But don't go nuts about it! 38% is a guideline, a starting point, an approximation. You won't be arrested or get struck by lightning if you end up at 36% or 41%. :) - Stuart -

RJHollins wrote:

Mira Music wrote:

I am having a devil of a time trying to work out 38% of 17ft!! :oops: Can anyone please tell me what to punch into a calculator to work that stuff out? Thanks!!

Convert feet to inches 17*12= total inches 38% would be total inches X .38

Thanks so much RJ! Embarrassingly I got 8% for Maths in my final year n high school. DOH!! Good thing I had an ear for music. :D

Soundman2020 wrote:

6' 5 1/2". But don't go nuts about it! 38% is a guideline, a starting point, an approximation. You won't be arrested or get struck by lightning if you end up at 36% or 41%. :) - Stuart -

Got it. Thanks Stuart. Too late about the going nuts part but I understand. HA -A

UPDATE So they added the 2x4's to the existing studs and hung the RC-1 the correct way. I stayed and watched the whole thing. I had to return to my current studio to make changes for clients then I went back and discovered they were on their second layer of drywall with the Green Glue. It was then I discovered they did not use backer rod. I called the contractor who told me they would be using it and he told me they used lots of acoustical sealant between each drywall join. I said this was not good enough so he said what he can do is he has a machine that will make the gaps between the joins then they will put backer rod in however this will only be on the outer layer of drywall. In the meantime the drywall guys finished the second layer. I need to know the implications of this. I checked the first layer as best I could and they used a very good amount of acoustic caulk between drywall joins plus they made sure no drywall was touching the floor or ceiling and none was touching in any of the corners. Then they caulked and sealed the gaps. I also made sure that no screws went into any studs by checking my own measurements of where the studs are and they matched their measurements exactly. They also used the correct length screws and when I banged and pushed on the drywall the bounce was there. So tomorrow morning at 8am we are meeting at Home Depot to get the door ( SOLID and heaviest I can find ) then we go to the site to discuss the backer rod issue. Any thoughts on this would be most helpful. Thanks!

I wouldn't sweat it too much. The backer rod is not life-or-death, as long as they have good seals on both layers, with correct size gaps filled with good quality flexible acoustic caulk, and they staggered the joints between layers, you should be fine. Backer rod is just extra peace of mind, but if the seals are good on both layers, and staggered, and flexible, then don't worry too much. What coverage did they use for the Green Glue? How many tubes per 4x8 sheet of drywall? (Just curious.)

So tomorrow morning at 8am we are meeting at Home Depot to get the door ( SOLID and heaviest I can find )

Make sure you get extra heavy-duty hinges, and really good seals! If you can, AVOID cutting holes through the door for mounting your latch: better to use a door-closer and plain old simple handles on each side (once again, heavy duty!). Cutting holes through the door reduces isolation a bit. If the door already has a hole cut, well, you can live with it, but it won't give maximum isolation like that. Are you going to "beef up" the door with extra layers of MDF or suchlike? It would be good if you can... You should have at least two full seals around the entire door perimeter (top, bottom and both sides. They should both be airtight. You might need to install some sort of threshold for the floor part, to get a good seal.

... and when I banged and pushed on the drywall the bounce was there.

The GG is not fully cured yet, but you should already notice that it doesn't sound like normal drywall if you bang on it: kind of a dull thud, with no "ringing" to it. Right? About the backer rod: I reckon they owe you a BIG discount for having screwed up like that! :) ( It ain't a huge deal, but they don't have to know that... :) ) - Stuart -

Whew!!!!! Stuart I was hearing you in my head saying..."What!?! Go back and make them rip it all out and use backer rod!!!" Seriously! I was nervous to post it! Hahahaha! Thanks for the info, most helpful. The door I have singled since last week is solid, heavy and has no hardware attached at all. I'm not sure how to keep it closed but I'll figure it out. More tomorrow with pics I promise.

I'm not sure how to keep it closed but I'll figure it out.

http://www.doorware.com/site/department.cfm?id=169205 http://en.wikipedia.org/wiki/Door_closer http://www.qualifiedhardware.com/door-closers-82/ :) Get a heavy duty one, since that door will be heavy once you beef it up. Stuart

What coverage did they use for the Green Glue? How many tubes per 4x8 sheet of drywall? (Just curious.)

I'll find out but they used 4x12's not 4x8's

Make sure you get extra heavy-duty hinges, and really good seals! If you can, AVOID cutting holes through the door for mounting your latch: better to use a door-closer and plain old simple handles on each side (once again, heavy duty!). Cutting holes through the door reduces isolation a bit. If the door already has a hole cut, well, you can live with it, but it won't give maximum isolation like that.

I picked out a solid undrilled heavy door from Home Depot this morning and am going to get the heavy duty hinges after this quick session.

Are you going to "beef up" the door with extra layers of MDF or suchlike? It would be good if you can...

I will but not immediately. The rest of the budget ( ha...right) is going towards interior treatments.

You should have at least two full seals around the entire door perimeter (top, bottom and both sides. They should both be airtight. You might need to install some sort of threshold for the floor part, to get a good seal.

I am not sure what you mean by two full seals. Where does the second one go? One on each side of the door? Any clarification would be good, thanks!

The GG is not fully cured yet, but you should already notice that it doesn't sound like normal drywall if you bang on it: kind of a dull thud, with no "ringing" to it. Right?

Will doble check that this morning. Thanks again for any contributions. I hope this thread is useful to someone else down the line. -A

PICS

More pics! Great! So it DID happen! :) A couple of comments: The Green Glue spread looks a little light. Probably not a big deal, since even low coverage still does good things for you! It's hard to say for sure, but from IMG_2780.jpg and IMG_2779.jpg it looks like they supported the inner-leaf ceiling drywall on top of the top batten that is directly attached to the outer-leaf studs! They should not have done that. They should have left a gap there, so that the ceiling drywall is well clear of the outer leaf, even with a small gap to the inner-leaf drywall, which is then sealed with caulk. You might want to check that they did that correctly. If not, then they have created a direct flanking path all around the entire room, from the inner-leaf ceiling to the outer leaf. That needs to be fixed. IMG_2784.jpg seems to show the same thing: the wall drywall and ceiling drywall seem to be touching, and they applied the caulk along that edge. There should have been a gap between them (where the backer rod should have gone!) that was just filled out to the surface with caulk, but from the photos it seems that there was no gap, and the caulk is just sitting in the corner. If so, that needs to be fixed. There also seem to be MULTIPLE penetrations by electrical cables, in both the walls and the ceiling! :shock: To me, it looks like they just went ahead and drilled holes through your brand-new high-transmission loss wall, and poked the cable through, with no thought at all as to what that does to your isolation! That also needs to be fixed. That's what I noticed on the photos so far. Maybe you can take some close-ups, to clarify these points? Regarding the dual seals on the door: You need one seal that goes all the way around the edge of the door, between the door and the jamb, and is totally air tight when the door is closed. Then you need another seal that accomplishes the exact same thing, an inch or two behind the first seal. Normally, these doors are built up in layers in order to get the mass that you need, such as by adding a thick sheet of MDF on top of the existing solid core base. You make that MDF a bit smaller than the door itself, all the way around, and you also build a second jamb on your door frame, that is a bit larger than the original jamb. The MDF mates with the second, larger jamb. You put the second seal in between those two. See page 94 of Rod's book for details on how to do this. It's very easy, when you understand the concept, and very necessary, if you need good isolation. - Stuart -

More pics! Great! So it DID happen! :)

Sure did!!! :D

It's hard to say for sure, but from IMG_2780.jpg and IMG_2779.jpg it looks like they supported the inner-leaf ceiling drywall on top of the top batten that is directly attached to the outer-leaf studs! They should not have done that. They should have left a gap there, so that the ceiling drywall is well clear of the outer leaf, even with a small gap to the inner-leaf drywall, which is then sealed with caulk. You might want to check that they did that correctly. If not, then they have created a direct flanking path all around the entire room, from the inner-leaf ceiling to the outer leaf. That needs to be fixed.

There is a roughly 1/4inch gap there. I know it doesn't look like it from the pics but I was obsessive about that and explained it to each guy on the team so no-one in the chain made the mistake. The gap is everywhere the drywall meets another layer of drywall so all corners, ceiling and floor. High quality acoustical caulking has been used to fill those gaps.

There also seem to be MULTIPLE penetrations by electrical cables, in both the walls and the ceiling! :shock: To me, it looks like they just went ahead and drilled holes through your brand-new high-transmission loss wall, and poked the cable through, with no thought at all as to what that does to your isolation! That also needs to be fixed.

Ok yes they did do that. So I planned to use loads of acoustical sealant to seal those holes. Is there a better way to accomplish this? I am still looking for an elegant solution to having my computer on the other side of the newly constructed wall which means another hole through the wall for cabling. Should I give up on this idea? One other thing...if you look at the picture attached you can see the storage space next to the Control Room. The Control Room has a ceiling but the storage space does not. It is exposed ceiling joists and goes up into the vaulted roof. The contractor is waiting for me to tell him whether or not he needs to put a ceiling in there. I don't care how it looks but what impact does it make to isolation? Need to know quite soon. That storage space is also where I plan to keep the MacPro Tower and drives so you can see where I need to make a hole for a cable run. Thanks again. -A

UPDATE Mudding and sanding is done. Painting and final electrical tomorrow then AC and finishing on Friday. Moving in on Saturday then the fun of acoustics starts! And more $$ shall be spent! Has no-one got any thoughts on the computer being in the storage space next to CR? And the best way to deal with the small holes for the outlet cables? Pics coming soon. -A

Has no-one got any thoughts on the computer being in the storage space next to CR?

I don't think that will be a problem. They wont be fully isolated, of course, since they will basically be inside the "S" of your MSM, but it will be better than having them in the room, that's for sure.

And the best way to deal with the small holes for the outlet cables?

Putty packs on the back. But that will be hard to do, as the walls are already built, so you can't get to the back! I don't think there is much you can do from inside the room to fix that. - Stuart -

UPDATE Room is finished! Apologies for disappearing but in the middle of this build I got kidney stones which was BRUTAL and had to move my entire family house and the studio. I will post pics and update everyone on the build and how we did it and the tested results. But I must say the isolation is very good. When I'm at about 85db inside there is very little you can hear outside. It depends on the music too of course. :D More coming soon, I just wanted to touch base so people didn't think I just flaked. -A

Wow! Kidney stones are no fun. Happened to me once, a few years back, and NOT something I would want to repeat! But good news about the room being finished! Looking forward to the update and pics! :) - Stuart -

WOW< You had to move the whole family just because you got kidney stones? What is that, a California law?

They CAN be tough out there !!! Especially Kidney Stones :shock: Glad you made it :D

LOL! Too funny! But not! :wink: Pics on the way....

Mira Music wrote:

LOL! Too funny! But not! :wink: Pics on the way....

Forum Rules Question: Is it really necessary to show pics of the 'kidney stones' to prove it happened ? :? :lol:

Is it really necessary to show pics of the 'kidney stones' to prove it happened ?

Errrr ... ummm..... Nooooo, I think this is one occasion where we'll all be more than happy to make an exception to the rule! :!: - Stuart -

ditto....

LOL! Double ditto! Although I have the offending stone in my possession.....hmmmmm....

Pity those stones have no useful acoustical properties - and even if they did, in terms of quantity required ... I wouldn't wish that on anybody.

If you used green glue and attached them to a panel absorber, they would add mass thus lowering the center frequency of the absorber.

LOL! STOP!! ENUF!! Hahaha! I'm going to wait for the bass traps to be delivered and installed on Friday before I take any more pics. Then I'll do a complete run through of the whole build with pics for each section as well as copious notes on how to do this with a contractor and what I've learned about Mini Splits! Watch this space! -A