The Dreamer stops dreaming!

Mondays' work is done, and what can we see?

Not an awful lot, unless we're looking closely. First fix electrical is in place for the Utility, Gym, and AV closet. The joists have been fixed in place. And the AV closet is framed. Oh, and the old joists and floorboards have been sprayed for woodworm - they should already have been done over the years, but there are so many little holes around, for the cost of a can of treatment, it'd be silly to take the chance.

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^^^ Joists fixed in place.

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^^^ AV closet framed, and FF electrics in. Separate ring-main for AV gear, lighting ring also - lighting will be controlled by RAKO units in this closet.

The next few images are Sketchup drawings I made to assist the builders in visualising what they're trying to achieve wrt wall and ceiling construction.

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^^^shows how joists are interleaved - such that the lower joists support the ceiling, the upper joists support the floor above. The two do not touch, so no sound is transmitted (in either direction) through the structure.

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^^^the same image from a different perspective. Showing how the inner wall (that supports the lower joists) doesn't touch the outer wall either. Again preserving 'isolation', prevent noise transmission through the structure.

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^^^more of the same, but also showing how there is to be insulation in between the studwork, and the leaf of the wall is constructed using double layers with a 'Green Glue' sandwich. In my case the double layer is one layer of OSB, then GG, then plasterboard (high density soundboard).

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^^^and one last view of all of the above.

Again, off to work in the morning, and not back until Sunday night. I'll be relying on my lad to keep me up-to-date. There should be lots to show, as they plan on starting boarding out tomorrow! Should start to look like a room.
 
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Proper job, nice to see :)

Some builders seem to have a hard time getting their heads around these methods of sound isolation. How are yours doing? Over on avs I've seen a case where they haven't listened and shorted out the ceiling, resulting in a partial stripdown of the finished room to correct it.

Gary
 
Luckily, my chaps have built studios for a radio station before now, and gone in on a second similar project and corrected someone else's mistakes.

Whilst this was 'ahem' many years ago in their 'formative' years, they are still very 'in-tune' with the principles of mass, isolation and absorption. They were even lifting and tying wiring away from the ceiling joists today before final fixing of the joists themselves. Earlier in the project they mentioned floating the studwork on neoprene on their radio station projects - something I haven't done here - you can end up disappearing down the 'rabbit hole', never to return - the budget has to stop somewhere!:suicide:

The one thing they had never heard of was Green Glue. When I showed them the video demonstrating the 'hammer test' on YouTube, they seemed genuinely interested. When I then showed them the YouTube video of how it's applied they looked somewhat less impressed!:rotfl:

I've told them to take some video of that if I'm not around!:D



 
In the US, one of the companies there uses a 'soundmat' product that is three different types or sizes of rubber crumb which they place on the floor and then float the new floor on top of that, and the new walls on top of the new floor. I just used ordinary rubber crumb carpet underlay as the rest of the room is compromised anyway. Plus the floor is uneven due to old suspended floor and extension concrete, so it leveled and smoothed it out nicely. But it's what I'll use in the future.

Gary
 
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Yep, I'm in a similar position too. The upper level of the floor (the level one enters the room at) is solid hardcore flooring (stone rubble and cement). It doesn't matter what I do, that part of the floor is compromised in being directly attached to the rest of the house. I'll be doing the same as you, in using a heavyweight 'crumb' underlay - I just have to hope that there is enough 'mass' in this floor slab to aid in the reduction of sound transference. I'm not a bass head, I need my hearing for work, so at the higher frequency levels I hope we'll be fine.

Although I had considered sawing slots around the perimeter; as I have heard of people doing that in an effort to create some isolation - but it's that rabbit hole vs budget again. As you know, Granroth over on avs has produced quite a thread on soundproofing techniques, and what works in the real world - and in his own build thread even went as far as testing sand vs fluffy in his stage to see if it makes any real-world difference in isolation - which sparked quite a debate.

It's why I'm not bothering building a concrete, or sand-filled door - it's just too much crazy for me! It will be a heavy door though (two solid fire doors joined together in a bank-vault fashion), but there are enough compromises already, that the concrete/sand sort of overkill would be a waste of resources. I think we'll end up with an OK space, possibly even better than OK - but I'm under no illusions that this will be perfect, or anywhere near the level of crazy we so often see over on avs! :laugh:
 
I completely agree - and Granroths results made the Erskine group go away and come back with a secret mix of sand and sawdust. Kinda like saying that sand filled stages don't work, although that's what everyone including them had been saying for years, and admitting it doesn't work after all. Their secret mix could mean that anyone else who does it and tests it with poor results doesn't have the correct mix, and you can only get t from EG. All sounds a bit suspect to me.

Generally though the basic principles work in the most part, and everything else is diminishing returns. Different levels of crazy indeed!

Gary
 
Was that the thread where they found no benefit to the sand filled stage?
Oops garys post popped up just after i posted mine, im guessing its the same thread i read.
 
So, I may be stuck in a hotel in Gothenburg, but my lad sent me a picture or two last night of progress - they're only phone pics, and taken by the light of a torch, but still leaves me quite excited.

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I'll get better pictures up on Saturday night or Sunday, but it's looking pretty good from what I can see here. The thin white lines in the corners is acoustic/intumescent sealant.

Can hardly wait to get home.
 
Thanks for all the pics and sketchup detail. In my head I'd never imagined the new ceiling joists off set like that to decrease the loss of room height. So simple it makes perfect sense but until I saw it I would have never thought of it. I love reading these build threads for new ideas and I always appreciate your updates. [emoji106]
 
Thanks, but I can't claim the idea as my own; I've done a lot of research over the last few years wrt sound 'proofing', and hope I've got a reasonable compromise when it comes to cost vs effectiveness.

A room can never really be made 'soundproof', one can only attempt to mitigate as much noise as possible, isolating lower frequencies is nigh on impossible, but the higher frequencies can be contained quite successfully with a few, relatively simple, steps.

The interleaved joists is not all that common in home cinemas, despite it being the very best solution to sound isolation. Most home cinemas constructed in the states are too large to span with unsupported joists, so people over there go for clips and channels to provide their isolation. It is in fact what I was originally planning; cost-wise, the two solutions are comparable.

(Actually, I should clarify the above paragraph. Any room that has a ceiling/floor already spanned by unsupported joists could in fact be isolated using separate joists - but much longer than 15' in length and the depth of joist required becomes very deep, which translates to a much higher cost. In my case, the cost difference between 8" joists and clips and channels, was pretty small, so why compromise?)

In the end, it's only the fact that my room is narrow enough that I can fit joists in, much wider, and the joists required would have to be much deeper, and it wouldn't have worked. As it is, the original joists are 12" deep, the interleaved joists (spanning a smaller width) are 8" deep, and still have to drop a fair way due pipe work getting in the way. One thing that helps too, is that one only has to consider the 'dead load' on the ceiling joists, there is no 'live load' - that is only a requirement for joists supporting a floor, which these do not.

Anyway, I have high hopes for the room; nothing is ever perfect, but whatever happens it'll be a huge improvement on trying to watch a movie in the kitchen!:blush:

The best source of ideas for soundproofing is Rod Gervais's book Home Recording Studio: Build it Like the Pros: Amazon.co.uk: Rod Gervais: 9781435457171: Books
 
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Back home now - and we'll rewind the clock, just to show my lads pictures that he took the other day before the room got boarded out.

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^^^fluffy insulation between the joists. They've also put noggins in to give the board edges a framework to be screwed into.

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^^^boarding begins.

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...and we end up with...

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^^^ detail showing independent studs for inner and outer wall.
 
...a mini update...

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^^^intumescent sealant along edges...

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^^^ GreenGlue being applied...

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^^^ two tubes per 8x4 sheet...

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^^^...and up she goes...
 
Looking good.....can't wait to see the next update. Looks like your contractor has the right tools I.e. lifting gear for the job. ;)
 
Close of play today....

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^^^ceiling up

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^^^a reminder of the scale

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^^^pipework for cabling and ventilation

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^^^comes into the equipment rack area.

More tomorrow!
 
Fantastic thread ! Love the last few updates. I,ve also been keenly reading up on sound proofing/reduction techniques , including the AVS thread and various you tube vids from Acoustic Fields. And you are spot on in regards the varying degrees of madness.

I've earmarked a few products which are on my wish list budget allowing, including the Norsound seals, green glue and OSB with 15mm plaster boarding.

In regards the interleaved stud wall and decoupled ceiling is there any point where you secure them to the outer wall for stability?
I've been considering the same in a 14ft * 22ft * 8.4ft room. I have a few design issues one being the door into the living room is fairly tight into the corner and not much I can do about moving it. So I,m a bit perplexed as what to do at the moment.

Still have several weeks of construction work for the extension, before the interior work can begin ...it's still the main family living area

Looking forward to your progress ...cheers best of luck
 
The inner stud work was temporarily attached to the outer walls in a couple of places whilst being built. Once the inner walls were up and the joists in place, the attachments were removed.

So, at the moment, the outer and inner walls are totally separate. This will change once the doorframe is in place, likewise the window dressing (we may see about the window area, but there is a heavy 'plug' to go there yet, so an attached frame may be safest). According to Rod Gervais, the small (relatively) attached areas such as door frames are an acceptable compromise in order to keep the door safe (it's going to weigh around 200lbs!)

As a slight aside, once the ceiling was up yesterday evening I had my lad jump up and down in the bathroom above the cinema. It was noiser than I had hoped; the joists holding the floor above are 22ft long and flex (I've put 22ft long joists in an on-line calculator, and it says it can't be done as a floor, only as a ceiling, and even then only with limited types of wood), the flexing seems to allow air pressure to build to the point where enough energy is transmitted to my ceiling (I could put my hand to the ceiling and feel the vibration) to transmit the noise, a bit like a passive radiator on a subwoofer I guess.

A very unscientific test, I know, and when I went up there myself and left my wife and lad in the cinema, they couldn't hear me just walking around with normal footsteps, only when I deliberately 'stomped' could they hear me, so I'm still hopeful that for movie watching we'll be fine. Time will tell.

Best of luck with your build!
 
Thanks for the info... I shall speak to.my builder to see what can be done. Part of the room will be exterior to the main house ( 3m). There will be supporting steel work put in place. I'm wondering how much this will transmit sound or whether this will break up the ceiling enough to avoid flex as you have detailed. Still looking at various products which can be used to put the beams on. Plus acoustic hangers ... I might invest in the book you have linked. It has many great reviews
 
Yes, Rod's book is great. Only a handful of chapters are totally relevant to us building home cinemas, but then they are so useful as to be mandatory reading for anyone contemplating such a project IMO.

Another mini-update...
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^^^walls being boarded...

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^^^more fluffy going in and outer walls starting to be boarded - no need for OSB on this side, so double layer of 15mm plasterboard will suffice.

The lads have their radio playing in the cinema - I can't hear it at all in the bathroom above; I appreciate there is no bass to speak of from a portable radio, but at least we know it works for the higher frequencies!
 
...and again at close of play...

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^^^room boarded out. Deep bed self-levelling compound applied to the upper level.

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^^^room looks bigger again with plasterboard...

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^^^facing back from the screen area

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^^^and more boarding out around the back.

That'll be it until I get back Sunday/Monday...
 
Just re-read most of this again I must start taking notes!

Re: the joists is this a proven technique? I would appreciate your views once it's all "sealed" and ready to rock. It's a great idea as I'm thinking of raising my floor to suppress the sound. Sound proofing as you say is a myth unless you live in a vacuum and after what happened to arnies head in total recall who would :D

If your putting on a mini bus for the main reveal so post the info as I'll happily RSVP as long as it's not Bognor Regis!

Hope the rest of the build flies along like this loving your detail in posts. Cheers.
 
You can really start to appreciate the difference the extra depth is going to give you. I was a little sceptical at first because of the increased cost of lowering the floors, but now its all boarded out it looks fantastic.

I bet you wish the rest of the floors could be lowered by the same amount to increase the volume.
 
......
Re: the joists is this a proven technique? I would appreciate your views once it's all "sealed" and ready to rock. It's a great idea as I'm thinking of raising my floor to suppress the sound. Sound proofing as you say is a myth unless you live in a vacuum and after what happened to arnies head in total recall who would :D

Yes indeed, in fact it's supposed to be the ultimate in isolation. The only thing I didn't do, was add mass to the floor above, as it's already got a layer of ply + tiles over it. There was so much pipework etc. in the way of putting more plasterboard between the joists (to add mass) I wasn't convinced it'd be worthwhile - the only downside of course, is that I'll forever wonder whether it could be better had I added the mass. :blush:

If your putting on a mini bus for the main reveal so post the info as I'll happily RSVP as long as it's not Bognor Regis!

Hope the rest of the build flies along like this loving your detail in posts. Cheers.

No mini-bus, but I'm about as far away from Bognor Regis as you can get whilst staying in England! :thumbsup: (I even refer to folk from North Yorkshire as Southerners! :D)

For soundproofing details, I'd heartily recommend Rod Gervais's book, Home Recording Studio - Build It Like The Pros - I think I linked to it earlier in the thread.:lesson:
 

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