Room within Room construction questions

how high are your ceilings?
I am planning to do the same for my theater, since it comes out much cheaper than buying the hat track and clips for decoupling.

I don't see this build as "flimsy" if you do it right; it will be just as building a structure within a room or not, it should be solid.
Others had used the clips attached to the top 2x6 header and to the existing structure.

soundproofingcompany website has a ton of info, but it gets pricey real quick, if you're on a tight budget like me, you'' use the ideas but might want to search for alternatives. Off coarse if you have deep pockets, its a different story.

What size room for your theater? any pics of the raw space?

Here is a span table for Southern Pine if you are planning to use the cheap stuff from the US. If you are using a different species there should be a table available somewhere on-line. Looks like 2x6s for sure.

http://www.southernpine.com/pdf/table17.pdf

On the foam issue you should have a discussion with your foam contractor. I had a discussion with a foaming guy at a home show and he showed me samples of different foams. There was one which he recommended where you wanted to control vibrational transfer. After curring it remained sponge soft. Not sure if it would work in your situation.

The primary problems will be:

1. Racking. You'll need (code in your area) RSIC-DC04 clips to provide some support between the foundation walls and the framing along with 1" steel staps in the corners.

2. 2x4 over a 14' span will not be allowed. You'll need to determine load (1 or 2 layers of drywall).

3. Your wall base plates will require isolation from the concrete slab.

4. You should install an isolation material (such as Acoutik mat) on the slab and then install a new subfloor over that.

Dennis, just to confirm (given that I'll be doing the same thing shortly), if you Isolate the walls and ceiling, you still need to do the floor?

This is some irritating in my case as I'll loose another 70-100mm in precious height.

The following diagram shows what you're suggesting I beleive (except I assume with Acoustik mat you'd just go mat-sheet flooring-underlay-carpet, with no battens):

That illustration would be incorrect for a room within a room; however, Acoustik Mat plus plywood subfloor would cost you about 23mm

About 20 years ago I helped a friend build a recording studio. We did rooms within a room construction and used 2x4's because of cost like you are suggesting. It does not have to tie into an existing structure as long as it is built like a house of it's own. For the ceiling we suspended the center areas using rubber isolating hangers from the hardware section of lowes. Then we used wire looped down just like you would on a regular suspended ceiling.

I would call your building inspector and ask them if this would fly with him or not... In practice it worked out great. The only issue we ran into with codes was emergency back up lighting and exit signs(because it was being used as a business) To keep the walls from being "flimsy" you will have to do a double top plate your top plate overlaps the bottom plate tying the walls together solidly.

Sorry Dennis I'm still a little confused about this. What you're suggesting is to cover the whole floor with Acoustik Mat, then ply and attach the walls to the ply, rather than having the walls sitting on their own "acoustik mat"/isolation material?

I am very familiar with the building codes in Province Ontario.
I am also familiar with the code in Nashville (or the lack thereof in many cases).

Ahh Dennis I was only refering to the suspended ceiling work he proposed. This was done in Clarksville actually where codes likely do (did) lack, however I can assure you 20 years later this place is still being used regularly.

As for lack in Nashville Codes, well mostly we are moving towards the IBC like most of the nation... I have been to Atlanta working as well. I mainly do commercial work, as a plumber. Amazing how codes can vary from place to place so greatly at times isn't it? Even more amazing is how one place has easier codes pertaining to one profession and stricter enforcement on another.

Just realized you had mentioned he needed clips on his walls. So I see they will not allow him to build a room as it's own structure alone. Disregard

BTW really have enjoyed what you bring to this forum, as many others as well. I was hoping this was the year to sell and build a new house, obviously the economy has changed things for me this year, good news is I should have enough knowledge gained by the time im ready to sell hopefully the next house is built cash.

I pmed Ted White about this question for myself.

He said 2" x 8" good for me (12'10" span)

So yeah maybe those would do for ya.

You might also want to look at HY engineered joists. They are lighter, cheaper, stronger and free of natural defects associated with solid wood beams.

They're made of OSB/Ply and look like a steel I beam, but timber. Your local timber yard will be able to advise on spans.

Not to hyjack the thread too much, has anyone got detailed drawings for floors in a room in room scenario. Tedd's website only outlines the walls and ceiling.

Great thread. It addresses many of the same questions that I am wrestling with at the moment and it does seems like the answers are scattered all over the place. So, without trying to hijack the thread, and in the spirit of consolidation, here are a few more questions/comments/suggestions which hopefully have general interest and relevance.

Some background: I have 3 concrete blocks walls (some of which appear to be unfilled (gulp)), a concrete slab, and a poured concrete ceiling in my basement/soon to be HT. One wall, the screen wall, adjoins a tenanted flat so I do want to make sure I can crank the sound up in the wee hours without having to worry about disturbing the tenant. A fourth wall will divide the basement into an office/study and will for sure use staggered stud wall construction and an exterior door. I am located in New Zealand. No permit is required for non-structural alterations which I am assuming is the category a room-within-a-room would fall under.

Questions:

- Is it even necessary to do the sound isolation thing given the concrete walls and ceiling ? I suppose I had better go through with it to justify the money I have already spent restocking on tools (mitre saw, compressor, etc) after having to leave my old ones in the US.

- What do people do for windows ?. The basement currently has an existing (single pane) exterior window. If the exit through the office is blocked by fire, I am probably going to wish I still had egress through that one window. But the current widow seems like a prime path for noise to escape..... I am thinking that a removable "plug" in front of the existing window might be in order.

What about doubling (sistering) a pair of 2*4 joists to in order to preserve height ? Actually, the ceiling is going to be black so I think a bit of sag would be acceptable aesthetically. And I can't imaging the structure based on 2*4's would actually fail.

What about going with 2*4 joists but putting a single dangling support in the centre ? Cut up a RSIC clip or something similar. Any more details on the "rubber isolating hangers from the hardware section of lowes" ?

What would the loss in sound isolation of RSIC clips/hat channel attached to the concrete ceiling be compared with full room-within-a-room (ie: ceiling joists sitting on the inner studs) ?

More details on options for isolating the bottom plate please.... Up until now I thought everyone just screwed, glued, or nailed (via PAT) their bottom plates directly into the concrete slab.

AFAIK, Green Glue is not available here in NZ. Also 10 mm (3/8 ") drywall is standard although 13 mm (1/2") is available at a premium. In any case, regardless of thickness, do I just double-up the bare dry wall or is there something else that could substitute for the GG under the "not as good as GG but better than nothing category" ? What about good old RTV sealant ?

If one is going to build a false screen wall anyway, it seems like there is the opportunity to put the center channel above the screen. The false wall can easily be framed strong enough to take the weight of even the heaviest center. So, psycho-acoustically, is it better to locate the center above the screen or below ? Since people talk out of their heads rather than their feet that would seem to favor locating the center above the screen. Although, come to think of it, for some people, the source often seems to be half way inbetween.....

Suggestion :

I was initially looking at an isolated floor but now think I will see how it goes first just having pad/carpet. Then I will try isolating the sub if necessary. Then, if that fails, I will go fully isolated floor. The point being that, apart from the hassle of ripping up an re-installing the carpet, this is one aspect of the construction that can be addressed later as needed. Like others, preserving every last inch of height is an important consideration.

Well, we are all packed and ready to go camping. That is the problem with having xmas holidays in the middle of summer. Other things to do besides working down in the basement. Did the white christmas thing the year before and I am thinking it is a bit over-rated. So, it will be a few days before I get a chance to check back in.

Brent

Span calculator http://www.awc.org/calculators/span/...Options#answer

A 14' span spaced at 16"OC will be fine with 2x6 Grade 2 or higher. This is conservative because you have no live load and less than 5lb/ft^2 dead load and using a deflection of L/360. L/240 could be used here too.

I hear ya.

Asked the local guy myself, and of course his question was, "well what it is going to be supporting" the I say double 5/8 drywall. He looks at me like what the hell??? (lumberyard in town 510 population) and says 2 by 8's should do, so I bought half of what I need.

2 bucks less than Lowes, I just had to buy em

Where code doesn't require structural integration, we will use a few (very few) clips to maintain square and prevent racking during construction. In the attached you can see where steel straps are used to prevent racking over the life of the space. An alternative to strapping is to utilize 1/2" plywood sheathing as your first layer followed by drywall rather than two layers of drywall.

If you'll note, the inner walls are constructed over the floor isolation system. If you do not do this, your inner walls will not be damped, or isolated, from the structure of the building defeating the basic premise of "room within a room" isolation construction. The true advantage of room within a room vs isolation clips, HAT channel, double drywall and Green Glue turns out to be the advantage associated with the additional depth of the wall cavities.

For the code mavens, this is a Virginia build.

As to the size of dimensional lumber for the ceiling joists...what do you use 2x6, 2x8 ... whatever. That depends on the span, spacing and anticipated load. If you find the post "fun ceiling", 100% of the weight of that mahagony ceiling, interior soffits, etc. are dead load on the ceiling (or isolation clips). In a good isolation design, the soffits are 3/4" MDF installed INSIDE the drywall shell of the room. This additional dead weight must be considered.

 

CottenFramingTwo.pdf 44.251953125k . file

There is absolutely no problem with putting acoustik mat directly on the slab.

If you take the approach you're suggesting, why not just frame out the space normally and do your isolation with clips and channel? It kinda seems like you wanna do a room within a room without really doing a room within a room.

As you wish. However, I would do Planton, Acoustik Mat, OSB for the floors.

If your contractor cannot install clips and channel correctly, they will not do stagger framing or wall within a wall correctly either. Regardless of the quality of the contractor we have NEVER in 20 years ever found a case where the contractor did it right. NEVER. Either they don't get it, their subs don't get it, or they don't supervise their subs. That level of supervision will have to come from you or a specialist you hire. There has NEVER been a case, where we haven't had to have things redone or we've caught stuff just before it was going to be done wrong (even in Toronto, Ottawa, Calgary and Vancouver).

Well, that's disconcerting. I did (and will do) the vast majority of work on my current room, but I'm hoping to move in the next few years and contract out the next room (it's too darn time consuming). If I have to watch over everything, I might as well do some of it myself.

Solid ... you need solid over a concrete slab? Maybe on the stage and seating platform, but over the slab?

This has been a most useful thread, many thanks to all for clariffying things.

No...the Maxxon products are nylon. Acoustik mat is rubber. I believe Ted White has it (or did). Here's another link.

http://www.acousticalsurfaces.com/ac...ustik.htm?d=16

The raw product is manufactured in Canada ... no I mean Quebec ... Ted would be your best source of information.

The manufacturer (Plate-Form CPT, PQ) does not sell direct. I believe they have an exclusive with a company called "Duro".

Thanks for the link. I had a look at the website and could not find any deflection data. Either deflection rate or maximum deflection.

Of course, Happy New Year.

Andre