STC?

nukmusic · Post by **nukmusic** » Wed Apr 23, 2003 8:54 am

Any thoughts on wall construction? I've read SAE's site, good stuff too.

What might the STC of my walls be? It's my new home's 20' x 20' 2 car garage that I want to use as a studio with as little changes as possible.

extisting walls are =

brick + 1" air gap + building felt + 7/16" strand board + 2x4 framing + 5/8" drywall. (no insulation).

I want to use these walls if I can without adding more, but if I have to I will. I have a 3' x 4' dual insulated window on one wall that I need to isolate, and also I will have to build another wall in front of the garage door. The rear wall(2x4 and drywall) leading into the house has a 6 x 12 walkin closet and 6 x 6 washroom behind it.

knightfly · Post by **knightfly** » Wed Apr 23, 2003 4:00 pm

Is the brick layer totally sealed, or can sound leak through cracks or gaps anywhere?

Having a second air gap worsens the STC rating compared to only two mass leaves with a single air gap. If the brick layer is airtight, I'd expect the total wall to have an STC of around 50-52, assuming EVERYTHING is caulked with a high quality silicone or butyl caulk; this isn't good enough if you have loud drums and picky neighbors, but would probably be fine if you use electronic drums and mix at normal (85 dB) levels, assuming you can squeeze mixing in between neightbors' lawn-mowing sessions... Steve

nukmusic · Post by **nukmusic** » Wed Apr 23, 2003 4:33 pm

I don't think the brick is sealed. It's a standard garage attached to a brick house. In the attic I can see the top of the bricks. I know I'll have to insulate the attic above the garage because it the only section in the attic that's not. just 2 x 10's and 5/8 drywall. This is a redesign of what John recommended, but without soffit mount monitors.

**** Is this right?*****

knightfly · Post by **knightfly** » Thu Apr 24, 2003 5:49 pm

Go here, and specifically read John's posts of Mar 01 and mine on Mar 17 - Try to understand just how many air gaps and mass "leaves" you are proposing in your walls. You would probably be just as well off just adding a couple of layers of sheet rock to the existing walls and forgetting the extra air gap, as far as sound control is concerned.

If you have to do it the way the drawing is shown because of the insulation being necessary, then that's the way it goes. Just read the stuff in the link so you'll better understand what's going on with wall construction. I hate to tell you to go ahead with this, because it's not the way I'd do it. It's also not the way to get best sound proofing, but it kinda looks like you're stuck. If so, good luck.

Also, I'd not put carpet in a studio at all, other than possibly a couple of throw rugs for "variable acoustics" - you get better sound in smaller areas with hard floors and absorptive ceilings... Steve

nukmusic · Post by **nukmusic** » Sat Apr 26, 2003 3:13 pm

Thanks, but the link is gone. "GO HERE"
I'm all ears I should or could do. Speak on Brother!!!

nukmusic · Post by **nukmusic** » Mon Apr 28, 2003 1:27 pm

Sorry for all the questions at once.

One more layer of drywall on the existing drywall?? Can I use a layer of fiberboard? I'm also trying to get the acoustic treatment correct. How do I sound proof the existing window? I have seen a dual window design that works, where another dual-insulated window is add to the interior wall of the existing window. and the Ceiling?

I did a test what my home radio(didn't unpack studio equip) in the garage to check the sound leakage. I think most of the sound (low end mostly) is exiting/entering through the attic vents (soffits), garage door, and a little through the existing window. As you see there wil be a wall build in front of the garage door. I may also insulate the door before building the wall. I know I will need to insulate the attic just above the garage because there is only one layer of 5/8 drywall and 2x10 joists separating the attic from the inner garage. Can I use the above attic as a low freq absorber or just insulate and add plywood in the attic? I'm greatful for any recommendations or changes you would make to my design.

knightfly · Post by **knightfly** » Tue Apr 29, 2003 11:40 am

Sorry about that, musta forgot to switch "Idiot Mode" off...

http://www.homer.com.au/phpBB2/viewtopic.php?t=86

I've got about 10 minutes to be outa here but will try to answer the rest of your questions tomorrow about this time... Steve

nukmusic · Post by **nukmusic** » Tue Apr 29, 2003 2:36 pm

I think I suffer from something called "OFF and ON Brain Shut down" myself

and sometimes "Bourbon Street 90-Proof Brain Lock" so join the party my man.

I also double checked the existing walls. It looks like Brick veneer, 2" air gap, felt paper, 7/16" shrankboard, 2x4 studs, and 5/8 drywall painted. concrete slab.

Michael Jones · Post by **Michael Jones** » Wed Apr 30, 2003 11:09 pm

Hi. Just thought I'd weigh in here.
Check the bottom row of bricks on the outside - are there any gaps or weep holes along the bottom row? I'd be VERY surprised if there weren't.
These "weep holes" allow moisture from condensation to escape.
If there are, I wouldn't seal them! and its doubtful that the brick is aiding much at all in the STC of your wall system.

knightfly · Post by **knightfly** » Thu May 01, 2003 4:43 am

I'd have to agree with Michael on the brick; if it's ventilated for moisture control, it's almost useless as sound control.

The good news is, if it's vented it's also almost "not there" in terms of an extra air gap and mass layer (since it can breathe) so you would then most likely see a serious improvement in STC by removing the inner wallboard, putting Resilient Channel up, and putting 2-3 layers of drywall over the RC... Steve

nukmusic · Post by **nukmusic** » Thu May 01, 2003 9:19 am

Yes I do have does darnnnnn moister holes.

I aslo think most of the sound is gett

This is the problem I have after doing some real hard thinking and reading more through this forum. The studio will only be in this location for about a year, then I'll move to a commerical building. Am I planning the design to much? I really want to be able to remove it with as little damage to the existing garage. And with that being said, I think my best bet may be the "BOX-IN-A-Box", if you agree??? I want a good design like i the picture just in the event that I don't relocate in that first year.

Slap me if you need to

P.S. Have you have any success with foam treatment products?(AURALEX) I may just build 2x6 walls(box-in-a-box) of the design and add foam treatment if it would work ok.

thanks for your help.

Michael Jones · Post by **Michael Jones** » Thu May 01, 2003 12:29 pm

If you think you may leave in a year, then I'd have the garage finished out like a new family room. Set your studio up in there for the time being, and when you sell, market the new room as a bonus room.