HELP with existing walls, need to soundproof as much as possible!

[millzboy]

Hey guys, I need some advice......


I built a studio in my home. What I did was use the extra car port in my garage and built a very heavy wall to make it a very nice 10x11 room. It's acoustically sound in the inside....BUT. There are 2 walls that are existing up against the house. I don't know how they are insulated, but it can't be much. I need to bring down the db levels as much as I can so that you can still function inside the house without the sound dominating.


What's the best way of doing that WITHOUT ripping open the walls? Again I don't need it totally silent (although I'd be fine with that), but as much reduction as possible.

Any recommendations? Spray foam? Sound proof wallpaper? I don't mind opening up small parts of the wall if absolutely necessary, but trying to avoid it.


Thanks in advance!


Mike

[Massive Master]

Building an additional, well-insulated wall on both sides is the more effective way. Studs, insulation, two layers of drywall. Inside the room, in the opposite room.

Quick, dirty and reasonably effective would be adding a layer or two of drywall to the existing wall - Both sides. I've found two thinner layers to be more effective than one thicker layer. If you have 1/2" up now, adding two layers of 1/2" on top. That'll be "pretty decent."

[RayMort]

Spray foam all the way!! With spray foam you don't need to rip down the walls you can just drill holes and fill and it will expand.) Not only is it an awesome sound barrier it can also work as a fire barrier (I don't know if that's it's official purpose but there was an article out awhile back about a guy who's music room was saved by the fact that he had insulated the walls with spray foam. You can buy DYI expanding foam insulation kits, and it's really pretty easy to do it yourself.

[jimmys69]

I have yet to hear of spray foam being a usable means of isolation. It may give benefits, but probably only a little. Typically, decoupling of structure between areas that need the isolation, and dense materials, is the only way to achieve good results. I may be proven wrong, but I have never heard of that as a viable option. I seriously doubt it tho.

It may help with voices, but low end frequencies are the hardest to stop from transmitting. This takes drastic measures to control.

[homestudioguy]

My walls are 9 and 3/4" thick.
ie doubled.
Half of the wall is dead air, the other half insulated.
Double layers of drywall too!

[chronicle]

The first clue is this...

What's the best way of doing that WITHOUT ripping open the walls?

In that case, you only have a few options.

1. Add mass to the wall OPPOSITE the studio.
2. Add mass to this wall INSIDE the studio
3. Add mass to both sides of this wall.
4. This one DOES require opening the studio side of the wall, which the "extra car port" suggests this was an exterior wall, with exterior sheathing. Did you drywall OVER this exterior sheathing or remove it BEFORE sheathing it with drywall? In any case, removing this material, whatever it is, would be required FIRST, because if you don't, it creates what is known as a THREE LEAF SYSTEM..which for certain LF frequency bands, is actually WORSE than doing nothing.

So, after removing this existing sheathing, frame ANOTHER wall a few inchs into the studio parallel with the existing wall, which creates a decoupling gap from the existing framing. Fill with batt insulation and then drywall ONLY the interior face(Studio side of new wall)with equal drywall thickness as rest of room. However, this method only gives diminishing returns, if there are existing structural flanking paths...ie..your other walls/roof/floor physically fastened to your house as well as the "weak link syndrome"...ie...thin doors/windows/common HVAC ducts etc etc etc.

And that's the problem with hindsight construction. Especially when it comes to Transmission Loss. You're fighting a loosing battle...ie...you will NEVER make it ..ahem.."soundproof". So you are correct in accepting you do not need it cause you'll never get it.

[meadeam]

what about ceilings? My studio is being constructed in an area where it will not share any common walls, but it will be beneath other rooms. I'm trying to figure out how to go about building the ceiling in the studio to best isolate the sound from getting to the rest of the house. I originally thought I would just insulate between the floor joists above, and double sheet rock it, but I'm wondering if I should try to keep the studio from being connected to the floor above at all? Like a box inside a box.

[AtoDeficient]

I seem to remember a pro studio somewhere using small, "Z" shaped metal hangers that suspended the ceiling drywall below the original ceiling joists. . . I don't recall how effective it was, but I imagine apart from building a complete room-in-a-room, it's the only solution. . . I went with standard 5/8 drywall, and standard cheap acoustic ceiling tile. . At some point, you gotta know when to say "when" . . .

[chronicle]

I'm trying to figure out how to go about building the ceiling in the studio to best isolate the sound from getting to the rest of the house. I originally thought I would just insulate between the floor joists above, and double sheet rock it, but I'm wondering if I should try to keep the studio from being connected to the floor above at all? Like a box inside a box.

Hi. There are a few ways to do what you are talking about. But first, let me clarify something. When you refer to what's known as "room within a room", you're talkin about serious isolation construction, which isn't cheap, nor easy to implement CORRECTLY. That's not to say it can't be done, but the amount of detail and prep is not for the faint of heart.

So, in that regard, let me suggest something else. You can get really good isolation using a few products that do not really make a room within a room, as that system is exactly what it implies. There are some products that "decouple" new drywall from existing framing by virtue of various hardware that have resilient pads incorporated into the design. There are floor isolators, wall isolators, and ceiling isolators.

However, as with any isolation construction, understanding the principles, proper planning, using the correct materials installed in the proper fashion, and paying attention to detail are the keys to successful TRANSMISSION LOSS construction.

If you are truly interested, start your own thread and we'll try to direct you in the right direction. This subject is far too deep to give proper direction in one reply. But just to give you an idea of some of the products, take a gander at these.

This is called the Isomax system for walls and ceilings.

is.php?i=361&img=isomax01.jpg

Here is a floor decoupling/dampening system. I don't remember the name but it ain't cheap. However, it's a lot cheaper than pouring a separate concrete slab.

is.php?i=401&img=rimc.jpg

The system is based on sylomer "pucks" embedded in a rollout layer of rigid fiberglass. You provide the subflooring and finish flooring

is.php?i=362&img=9397rimw.jpg

For a cheaper solution for the walls, there is Resiliant Channel, but I don't have a handy pic of it. Just do a search.

Btw, the reason I show things for walls and floors instead of just the ceiling, is because of FLANKING PATHS. To attempt isolating a room from a space above without addressing the space as a whole, is a lesson in hindsight. In fact, without knowing the particulars and existing conditions of your space, it's actually impossible to ttell how to do this. And sometimes, it IS impossible to achieve iso goals, given various factors. So, start your own thread and we'll go from there.

[chronicle]

PS. All these systems require the REMOVAL of all existing drywall to function correctly. Among other things. Other than that, all you can do is add mass, but at some point there is diminishing returns.