John Sayers' Recording Studio Design Forum

Guys,

A couple of quick questions:

(1)Should I plaster or caulk these gaps around my window frame where the new layer of wallboard has run just short.
I am thinking caulk as it will allow natural movement of these window frames but will the isolation still be OK?

(2)This wall will not be seen or painted as a new inside out wall will go in front of it. I am applying three layers of plaster and jointing tape to all seams and screw holes as per normal plastering procedure but is there any benefit in spending additional time sanding this back after the final layer of plaster has dried.

Thanks as always

JohnG

Am I missing something here? Your "limiting factor" for that leaf of the wall is the window itself. Caulk will seal that gap better than plaster will. Ultimate isolation can only happen if that window is eliminated IMO.

The window will be sealed of course!!

I think the point Xalky is making is that, even if that window is totally sealed up, the glass itself is likely less mass than the wall it's a part of. This makes the window the "weakest link" in your outer leaf.

This is an important point, because no matter how good that wall is sealed up, more sound will escape through the window.

Myth: If you have a bad window on great walls with a great floor and great ceiling, you will have only "slightly worse than great" soundproofing.

Fact: If you have a bad window on great walls with a great floor and great ceiling, you will have only "slightly better than bad" soundproofing.

That being said, caulk is probably your better choice, but Xalky is correct in saying that the most correct solution from a soundproofing perspective would be to remove the window completely, filling the hole with wall.

Thanks Sharward,

I think maybe eveyone is confused by what I am actually doing with the window. I am not just leaving the glass there, obviously that will be a waste of time as its very thin and not airtight.

I am screwing and glueing and sealing a 20mm panel of MDF straight over/onto this window frame. It will totally cover these windows and will be airtight.

This will be more "Mass" than the actual wall boards are in this part of my system!!.

PS- before I get told its three leaf please note I have discounted the glass as a leaf because its not sealed or airtight - any reduction in db because of this, I can live with.

I am asking about the seams around this window (as you can see in the photo) not the window it-self.

JohnG

Don't you love it when you ask "question A" and get answers to "unasked question B"?

That's good that you're putting some mass in that window cavity.

So, John, do you still have questions (if so please post specifics) or have they been addressed?

Also, you have glass, then covering with the 20mm MDF - what were you considering to be a third leaf? (And yes, even unsealed the glass will act as a leaf; just not a very GOOD one, and mainly in a BAD way) Steve

_________________
Soooo, when a Musician dies, do they hear the white noise at the end of the tunnel??!? Hmmmm...

Steve,
Pretty sorted now with answers - will post an update in the next few days. I have been a busy boy with the sander and caulk gun.
Justy about ready for insulation.
JohnG

Just a quick update seeing it's been a few weeks.

Photo one:The new layer of plasterboard is installed, taped and sanded.

Photo two:All seams around top, bottom and windows are caulked.

Next step is sealing the windows with 32mm of MDF, then staple 75mm insulation to these walls and then get my builder mate around to start cutting the inside out walls that will sit 75mm from the walls you can now see.

Progress costs in this game!!

Another update:

Photo one: Windows sealed with 32mm MDF, screwed and caulked.

Photo two: 75mm stapled to beefed up walls and sealed windows - alot easier than I thought it would be!!.

Frames for inside out walls being cut this Friday!!

JG

Insulation compleated!!
Of to Aussy this weekend for a weeks work and the Rugby (AllBlacks verse Wallabies).
Might bump into John, never know!!
JG

Guys,

I have 66mm stud cavities that I will need to buy insulation for shortly.

In New Zealand our options are:

Rockwool and Rigid Fibreglass Panels - Thickness: 25mm, 50mm, 75mm, 100mm

Normal Pink Fluffy Fibreglass - Thickness: 50mm, 70mm, 90mm

Sound Control Black Fluffy Fibreglass - Thickness: 75mm, 100mm

I am not sure what thickness to use as 50mm is 16mm to thin and 75mm is 9mm to thick and will stick out to much.

What do you all recommend - How about 50mm rockwool or rigid fibreglass panels pressed up to the plasterboard? I will have 16mm of air in the walls at the front but at least this way once the cloth covers the walls I will have a flat wall.

Thanks

Anyone?

Well framing started today - pretty easy really only took 2hours.

I am running 10mm rubber on top and bottom of these walls, which you can see on the left of the second picture, so we measured each stud to make sure we get a nice snug fit whan we lift the walls.

I will be glueing on the rubber playmatt tomorow and screwing the 16mm plasterboard on once the glue has dried.

Should have walls stood this week I hope.

Couple of shots:

Sam the builder and walls ready to go!!

PS-still waiting on any replys on the above insulation question

Very interesting "grid" framing. Hey, Doni -- what do you make of it?