Choosing fiberglass

knightfly · Post by **knightfly** » Sun Oct 16, 2005 4:03 pm

Julian, do you have any of the higher density insulation already? If so, you might try this

http://www.johnlsayers.com/phpBB2/viewtopic.php?t=4013

It's a relatively cheap way to find out how much of your drums are coming thru the floor; if it helps, great... Steve

Julián Fernández · Post by **Julián Fernández** » Mon Oct 17, 2005 8:47 am

Great thread, i really missed it... it´s surprising that a riser can make such a difference..!
The thing is, i didn´t order the wool yet, ´cause i was waiting to be sure what procedure i´m gonna use.
Anyway, i need to improve the insolation far beyond "between 65-70 dB" (the result exposed by Dieter@be on the link).

I have an idea, and i´m not sure if it´s crazy... let me know.
If i take a driller and i make several small holes on each hollow brick, i´m virtually distroying one of the masses of the brick, right? I mean, the only mass will be the outer face of the brick (which is rendered).
This way, i can start building the new gypsum room without compromising the low freqs response. What do you say?

knightfly · Post by **knightfly** » Mon Oct 17, 2005 8:00 pm

Doubt if that would work like you want it to - more likely you'd end up with a mid-range helmholtz absorber, which would weaken the wall more at the resonant frequency. Depending on the size of the holes, that frequency could run anywhere from maybe 100 hZ up.

Drilling holes in a third leaf doesn't make it "go away", because air is a stiff enough spring that it can't get out of the way fast enough to stop having an effect on close surfaces.

Please refresh my memory; your sisters bedroom is below the studio? Or am I thinking of someone else? Just how much isolation DO you need for drums? Steve

Julián Fernández · Post by **Julián Fernández** » Mon Oct 17, 2005 11:48 pm

Hey GOOD memory Steve! My syster is right under the studio...
Anyway, i make some raw tests and she´s not the one who suffers the most the sound of my drums... the floor is 30mm concrete and somehow it stops the sound on the drumkit (at least, more than the walls). With i riser i think i´ll be able to forget about disturbing her.
The way i see it is, i need as much insolation i can afford. I play about 4 hours a day, and i need to play without taking care about annoying people.
We discuss a lot o possible constructions (here on the forum)... and i learn a LOT (really), the last thing left to do is choosing the right procedure and give it a try. I certanly won´t blame no one, ´cause i know the risks of working with hollow bricks, but, i can´t do anything about it... so, with your priceless help i think i can make a really decent studio. BTW, i´m NOT into heavy, so forget about a band banging at 160db (like the bands that Hugo have to take care of). I´m into jazz, fussion and latin. Anyway...

What´s the best option for insolation? Should i forget about the room within a room approach?

Didn´t you have a soft to predict STC of different type of constructions? I may be usefull in this case. What do you think?

Thank you again, and let me say all you guys keep surprising me, with your time and dedication... God bless you.

rod gervais · Post by **rod gervais** » Tue Oct 18, 2005 5:19 am

Julián Fernández wrote:Great thread, i really missed it... it´s surprising that a riser can make such a difference..!
The thing is, i didn´t order the wool yet, ´cause i was waiting to be sure what procedure i´m gonna use.
Anyway, i need to improve the insolation far beyond "between 65-70 dB" (the result exposed by Dieter@be on the link).

You have your work cut out for you big time with that requirement.

f i take a driller and i make several small holes on each hollow brick, i´m virtually distroying one of the masses of the brick, right? I mean, the only mass will be the outer face of the brick (which is rendered).
This way, i can start building the new gypsum room without compromising the low freqs response. What do you say?

This would work IF you were to fill each of the cavities completely with expanding foam.

Although the foam will add virtually no value to the wall from a mass point of view - it will effectively damp the multiple faces so they act as one.

Rod

knightfly · Post by **knightfly** » Tue Oct 18, 2005 6:33 am

Finally, a good use for "Great Stuff"

Thanks, Rod. Hadn't seen you around for awhile, guess your schedule's back down to "only ridiculous" ??!? Mine too... Steve

Julián Fernández · Post by **Julián Fernández** » Tue Oct 18, 2005 6:41 am

Cool idea, Rod!

So, we´re back to 2 layers of gypsum, 16kg/m3 wool between the steel studs, 10cm air and my now-foam-filled-hollow bricks wall... right?
What a team you make guys!!!

Julián Fernández · Post by **Julián Fernández** » Thu Oct 20, 2005 6:42 am

I have a couple of doubts about how to finish the walls...
From the specs sheet of my local gypsum retailer, when installing a gypsum board, you should a 15mm gap between the gypsum and the floor to avoid moisture to travel trought the floor and touch the gypsum.
Since i wanna float the walls but no the floor, i do have to 2 spaces to fill (i think)-between the neoprene pads and between the gypsum and the floor-. Check the pic.

So, how should i place the gypsum on my case? Touching the floor and caulking or leaving the gap and filling it with wool or some kind of rubber?

This pics shows the way gypsum is installed here in Argentina. Just to be sure, can you check it to see if something missing?

Caulk:
I read the sticky about it, and go trought the discussion about brands... but, besides the gaps created for cables, where should i caulk a wall?

As always, THANKS...

knightfly · Post by **knightfly** » Fri Oct 21, 2005 2:19 am

Julian, your concrete is not a ground floor so moisture shouldn't be a problem; still, the proper way to build soundproof walls works either way. Your pix of gypsum install look fine. I've done 3 sketches that will hopefully explain more.

Neoprene should NOT be surrounded by any hard materials when used to float objects; this makes the neoprene MUCH harder and less compressible, so it changes the entire equation DRASTICALLY. I don't know that you're doing this, just a reminder. In order for neoprene or any typical rubber to act as a spring, it needs someplace to "squish out" or it becomes nearly as hard as a wood frame.

The only place necessary to seal your walls is around the edges of the gypsum - not necessary to seal frames to wall or floor, etc.

HTH... Steve

Post by **sharward** » Fri Oct 21, 2005 3:15 am

Great illustration and great explanation.

Julián Fernández · Post by **Julián Fernández** » Fri Oct 21, 2005 4:46 am

Brillant, Steve, as usual...

Now... Should i use Open Cell Foam Backer Rod, right?
There´s any other thing to replace it -quick search tells me it will be hard to find it here-?

BTW, Should i muld and tape every layer of gypsum or just la last one?

Take a look the way my gypsum layers are going to be placed... Any other place to caulk?

Thanks!

knightfly · Post by **knightfly** » Fri Oct 21, 2005 11:37 am

Backer rod's typically closed cell, doesnt' matter because it's not doing anything acoustic.

Mud and tape each layer everywhere EXCEPT around the edges of the entire wall; backer rod and caulk the perimeter. In other words, caulk where the red lines are and mud/tape/sand where the question-mark is.

http://www.loghelp.com/backerod.html

The closed cell on the left is what you want; if you can't find it locally, you might be able to order on the net... Steve

Julián Fernández · Post by **Julián Fernández** » Sun Oct 23, 2005 11:12 am

Hey Steve, i found backer rod near home!

Cool!
Yesterday i receive the Mason neoprene pads... Gypsum arrive next week. Finally, things start to happend.

BTW, Why don´t you repost the drawings that you just posted here on the caulking sticky thread. They´re very informative.

Next questions, after start framing..!
Thanks man!!!

Julián Fernández · Post by **Julián Fernández** » Sun Oct 30, 2005 8:39 am

Started framing today! Check it out..!

Check the circle on the pic of the pads... I´m floating the walls, but it´s REALLY hard to cross the screw right on the center of the pad... So, i´m put a couple of pads with the screws off center (where the red circle is), and the rest of it will be glued to the floor and the sole plate, to avoid unnecessary screws...

Anything wrong with that?
Anything else to keep in mind while framing?

Thanks guys!!! Enjoying it so much, so far...

knightfly · Post by **knightfly** » Mon Oct 31, 2005 3:05 am

The minute you put ANY screws thru frame, pad and floor you've just eliminated any reason for using the pads at all. Please stop, and post a sketch of EXACTLY what you're doing - show floor, pad, base channel of the wall, screw, and anything else you're doing including what touches what, and where.... Steve