River Nile Build

[Soundman2020]

Question: I assume you are doing star grounding? If so, then you already have your answer (you need a separate ground conductor for each receptacle, or at least for each box). If not, then why not?


- Stuart -

[Rivernile]

Stuart
I'm not shure i understand your reply.
What i was asking is,since i already ran the receptacles using 14-2 wires which only has 3 conductor in it.
At this point am i losing anything if i forgo the task of pulling out all that and replacing it with 14-3 wire .
I mean what am i losing if i don't do star grounding?

Also, for the silent boxes for the HVAC do i have to put a silencer on the returns?or only on the sends?

[Soundman2020]

what am i losing if i don't do star grounding?

If you don't do star grounding, then you are gaining.... you are gaining the probability of suffering from ground loops, and incurable mains hum in your studio. I see it all the time, and believe me, it is a problem that you do not want to encounter. Always very easy to identify, and usually really hard to solve. Just today I was asked to check out a major hum problem in a church sound system, and found 28 volts on the ground in some of their sockets , and 2 volts in others : Turns out the building used to be two separate houses, and some genius "electrician" tied the two systems together... It is going to cost them big money to fix that now.

You might find this thread interesting:

http://www.johnlsayers.com/phpBB2/viewt ... ar+ground+


- Stuart -

[Death By Darwin]

Just an idea on the fire blocking issue, I was pondering how I was going to accomplish this and a friend of mine suggested cutting up a fire blanket and stapling strips of the blanket across the gap at the top of the walls. Could work? i think fire blanket is a bit pricey, but should be able to stop the spread of fire and hot gasses...

[Cold]

I personally would not do this as the blanket would not create a proper smoke seal, is not a tested system and probably would be more expensive than a proper system.

[Rivernile]

I have a Question about adding mass to walls
Should i add a layer of plywood on the walls before i put up the two layers of sheetrock?

A friend suggested that i add ply first so that later when i add the sheetrock, i dont have to search for studs when doing accoustics in the room.

What do you guys think about this?Is it a EXPENCE I COULD FORGO/

I plan to use green glue between the layers of 5/8'' sheetrock.

[Soundman2020]

You could do that if you wanted, yes. Having a nailing surface everywhere under the drywall is useful. It also adds structural strength to the wall, which is good. Andd mas, which is also good.

You don't HAVE to do it, but it won't do any harm if you WANT to do it, and will actually help, for several reasons.


- Stuart -

[Rivernile]

Thanks Stuart,
I am just at that point now where i am questioning every single additional cost because i know i am way over my original budget.

So since i am going to use green glue,from a scale of one to ten should i just bite the $250 BUDGET and get the ply?

or just forget the ply?

[leadvox]

Does anybody have any idea whether this would meet code as a fireblock in a residential studio build, either alone or with rockwool? I figure it might be easier to apply than caulk, but I want to make sure it's okay to use.

http://building.dow.com/na/en/products/ ... eblock.htm
http://www.acehardware.com/product/inde ... =205008464

[Cold]

I would talk to the people who make it, they did provide a link. Honestly I have never used it, but I work in commercial construction in Canada. We are waiting for a foam to be approved and then we will be all over it.

So, short answer, If it has passed for your application, I would use it. Please note the .5" maximum hole size. If you need to fill a larger gap, this is not your solution.

Talk to the manufacturer, ask for paperwork. If everything checks out you are home free.

Just don't shortchange your safety.

Steve

[leadvox]

Yes, the .5 in. max was an area of concern since this is for the fireblock between my inner and outer frame rather than small penetrations, though I did think that placing rockwool in the gap might help and give it something to adhere to. It is UL tested.

[rod gervais]

the use of rockwool is good - but don't over-pack it or it will create a flanking path between the 2 walls.....

As far as the foam goes it is not approved for joints larger than 1/2"....... your joint is (apparently) larger than that regardless of the backer (for example - it is not approved for joint larger than 1/2" even if they have backer rod installed.

It is not a matter of backing - but rather a matter of how long it last in the presence of flame......

It would actually expand and fill up a joint larger than 1/2" - but it would fail under fire conditions with joints that large.

Use the rockwool and caulk either the underside or top side (whichever you can get to easier) with a commercial fire caulk...... that is an approved firestop.

The fire caulk handles hot gas and the rockwool handles the flame.

OR - at the top of the wall pad it out with drywall to shrink the joint to just 1/2".... then you can use the foam....

Either/or will work.

Rod

[leadvox]

Great! Thanks! That's kind of what I was thinking. Any idea of how large of a space the caulk can cover (using rockwool as backer rod)?

[rod gervais]

Great! Thanks! That's kind of what I was thinking. Any idea of how large of a space the caulk can cover (using rockwool as backer rod)?

The caulk can cover joints as large as you want them to be - however the controlling factor here is not the caulk - but rather the backing.

You have a limit of how wide a joint you can make with the rockwool of probably a 1 1/2 or so - larger than that and you would have to pack it too tight in order for it to hold itself in place - and packing it tight enough to do that would create the flanking bridge I explained earlier would be a problem.

I generally try to hold joints to about 1" when using that system....... anything larger than that and I build out one of the walls to create a hard fire-block that shrinks the joint down to 1".

Then you can use a 4psf rockwool and pack it to just 40% density....... it will stay in place and not be so rigid as to join the walls together...

Rod

[leadvox]

All of the mineral wool is installed, so some progress is being made on my build!

I spoke with the head building inspector for my city today and he says that the mineral wool is sufficient for fire blocking and that no caulk is required since this is a residential single family home. Does this sound accurate to those in the know?