Isolation? Do I have this right?

Tapp · Post by **Tapp** » Tue Jul 20, 2004 1:16 pm

Hi,

I'm new to this forum and have greatly enjoyed reading over much of the great info and knowledge that is present. I am building a project studio in my home and wanted to get some feedback. I've read a lot of the "sticky's" and been to other forums with searches and these are some of my plans.

My studio will be a 1-room setup with mobile gobos to isolate live drums, vocals, etc. I play/record mostly rock style music with some mellow acoustic ballads thrown in.

My room is the former garage and it measures 18'7" X 21'6.5" X 9'. The garage door has been removed and bricked in. The whole house is connected to a common concrete slab and the attic area is common to the whole house 1-story. There is probably a good 5' of space in the attic area to the tip of the roof pitch.

2 of the walls are interior and 2 are exterior. The exterior walls from outside-inside are as follows: brick>1/2"osb plywood>2X4studs on 2X4 sole 16"o.c.>1/2" drywall. The "bricked-in" garage door opening has no interior drywall, just 2X4 16"o.c. frame at this time. The other "existing" drywalled wall is NOT insulated.

The 2 interior walls are different. I have just built one of the walls and it consists of 5/8"drywall>2X4studs/sole 16"o.c. 36" door opening and only doorway into the studio (the interior/studio walls have not been constructed). The other "existing" wall is 1/2"drywall>2X4studs/sole 16"o.c.>insulation>1/2"drywall.

The ceiling is flat textured drywall (1/2") connected to 24" attic joists.

MY PLAN:

Cut all of the existing interior drywall inbetween the studs and use it (in the bays) inbetween the studs on the 2 interior walls (glued). Cut the existing ceiling out too.

In this order:
Go back with rockwool insulation between the studs (2-3" rolls).
Resilient channel on ceiling and walls
5/8" drywall
Volara limp mass vinyl from "Foambymail"
5/8" drywall

On the ceiling: RC>1/2"drywall>limp vinyl>1/2" drywall.

Does this sound like a reasonable plan and how much isolation should I expect? My budget is limited so am I wasting?

On the drywall installation, how do I treat all of the seams. Do I caulk the first layer and float out the final layer? Also, where and when do I use the acoustic caulk in the install process for both ceillings and walls?

thanks so much!!

Tapp

AndrewMc · Post by **AndrewMc** » Tue Jul 20, 2004 5:52 pm

A diagram would help showing the wall detail - its a bit hard to follow with out that. I'm not sure if your interior walls are doubling up the external walls or they are just internal framing.

To save money - you could drop the limp mass vinyl - that stuff is way expensive. A good substitute at a fraction of the price is roofing felt (the stuff with small rocks in it). H-Depot sells it for about $12 a roll (each roll weighs about 100lbs)

Tapp · Post by **Tapp** » Wed Jul 21, 2004 1:42 am

Thanks Andrew,

Yeah I've got a rough diagram drawn that suits my needs now. I'm taking the project one stage at a time. Right now I'm just concerned with the soundproofing issues and how to construct using RC and such.

Have you used this roofing felt with success?? Do you think it would be hard to sandwich with the grit on it? Is the fire rating the same with the limp vinyl?

A diagram would help showing the wall detail - its a bit hard to follow with out that. I'm not sure if your interior walls are doubling up the external walls or they are just internal framing.

Two of the internal walls are finished in sheetrock, the other 2 walls are exposed studs as of now.

Tapp

Hashbrown · Post by **Hashbrown** » Wed Jul 21, 2004 1:55 am

In place of the roofing felt, you can also use TP-4 GAF Tri-Ply rubber roofing. Its about the same stuff without the granules. Its available at Home Depot in the same section as the roofing felt. I plan on using it for my ceiling in between the joists and another layer of sheetrock to add mass to the floor above me. Could also be used where you are suggesting. I believe its been used successfully by a few people on this board.

AndrewMc · Post by **AndrewMc** » Wed Jul 21, 2004 2:20 am

I used the roofing felt - I put it in the external wall between the studs & then a layer of drywall on top to add mass to the external wall.

The drawing would help to comment on you wall setup - I couldn't follow the text too well.

Innovations · Post by **Innovations** » Wed Jul 21, 2004 4:02 am

Interesting, I hadn't thought of using roofing felt to add mass. It it true that the mass-loaded vinyl stuff is expensive (and even more expensive to ship) although I have found significant differences in cost between suppliers.

For those of you who have used roofing felt, did you install with mastic, roofing nails, or what? Did you butt ot lap the seams or take some other measure to prevent a leakage path.

AndrewMc · Post by **AndrewMc** » Wed Jul 21, 2004 4:15 am

I didn't use it between layers of sheetrock - but if you were going to do that you could do it fairly easily - just mud the 1st layer and then the roofing felt should adhere to the wall well enough to get the 2nd drywall layer on top of it and screwed down.

It should add some value, although if you are building double framed walls with a decent air gap and 2 layers of drywall either side of the double wall you shouldn't need it - that configuration alone will stop all the sound you need and and sound is going to be coming thru the weak spots like doors etc.

Tapp · Post by **Tapp** » Wed Jul 21, 2004 4:39 am

Andrew,

How do you treat the first layer of sheetrock once it's installed to the RC? Would joint compound or acoustic caulk be better for the seams?

None of the ceilings or walls should touch each other correct? My understanding is you leave about 1/4" between wall corners and ceiling? You would apply acoustic caulk to this gap and then tape/mud over that? Is this the proper procedure?

Thanks Hashbrown, I'll check around for roofing material. That would definitely be cheaper than both Sheetblok and Volara.

Thanks all!!

Tapp

AndrewMc · Post by **AndrewMc** » Wed Jul 21, 2004 6:50 am

I only used RC on the ceiling - but it would be the same as for walls.

This is what I did

- screw the 1st layer of sheetrock to the RC using self tapping screws - caulk between every joint. Take care not to put any screws up into the joists (if you use 1 inch screws then they will not reach the joists thru 5/8 sheetrock)

- 2nd layer, run sheets in opposite orientation to first layer. I caulked over every joint on the 1st layer and then put mud over the whole first layer, then using far less screws - screwed the 2nd layer into the RC also. I kicked 2/4's under the sheet to make sure it was pressed up well. Mud makes very a very strong bond between drywall sheets.

You are correct about leaving the 1/4 gap. When you put in the sheets stand them on shims cut to size and cut the sheet itself to size to leave the right gap at the top. Caulk well before you put up the sheet and then after its up. With the finished walls I didn't mud these gaps - I just used caulk and wiped it with a cloth so it looked neat.

Tapp · Post by **Tapp** » Wed Jul 21, 2004 11:27 am

Thanks Andrew, that's just what I was looking for.

Tapp