Caulk specifications

Michael Jones · Post by **Michael Jones** » Sun Apr 13, 2003 8:08 am

I have nearly completed the first layer of a multi-layer wall system for the EXTERIOR of my studio.

The construction is staggered stud, and the sheathing consists of the following:

1.) 1/2" OSB
2.) 1/2" R-MATE (This is an insulative material made of compressed fiberglass insulation. One side is reflective, and the other side is not. This material is required by LOCAL building and energy codes where the finished outside walls will be either brick or stone.)
3.) Tyvek House wrap.
4.) 1/2" wood siding
5.) Brick

The brick extends half way up on all sides except the front, and there it extends all the way up.
Because brick is required to have "weep holes" along the bottom course, I don't expect it to have an added benefit in STC ratings. It is there purely for asthetic reasons.

So getting back to the first layer; the OSB:
I am ready to caulk the joints and have chosen the caulk I intend to use. It is an elastomeric latex sealant with a tested 50 year durability guarantee.

It meets the specifications of ASTM C-920, Class 25.

A search for this specification yeilded only sites in which you have to pay for the actual specification document.

So given that, does anyone have access to ASTM documents, and if so, does this caulk prove adequate for studio construction?

Michael Jones · Post by **Michael Jones** » Sun Apr 13, 2003 8:09 am

"knightfly" one of our resident construction "experts", maintains that construction should be "...to cabinet makers tolerances...".
Attached is a close up picture of a typical OSB joint. Its hard to tell in the picture, but you can't even fit a razor blade between the joints!

This is NOT difficult to accomplish. Take your time, measure twice, cut once, and when placing the panels up to be nailed, pull the joints together tight, and then nail each panel with the nails driving into the stud at opposing angles. This actually pulls the joints together. Just a tip for anyone at this stage of constrtuction.

knightfly · Post by **knightfly** » Mon Apr 14, 2003 12:31 pm

Michael, here's a link to the OC stuff, where you'll find a downloadable PDF on their Acoustiseal - they claim it EXCEEDS the spec you mention, as well as citing several others.

http://www.owenscorning.com/around/soun ... /caulk.asp

AFAIK, if you don't go with either this or the USG version, the thing to look for is either silicon or butyl, with the term "non-hardening" being mandatory. I'm still too far behind from a 2-month long battle between me and every cold/flu/pneumonia symptom in the known universe to have gotten there yet, but one of the projects I have on my Acoustics list is to check the Home Depot, Lowes, etc offerings on caulk, etc, and compile a list of "acceptables" - As far as caulk goes, it is MANDATORY that it won't harden or shrink, nearly as mandatory that it has good sound-blocking properties (which probably means heavier bodied than most) and the rest is kind of optional.

EVERYBODY - Michael brings up an excellent point that I tend to forget, since it's kind of automatic by now - NAILING.

When I nail panels on studs, I ALWAYS point the nail about 30 degrees off square, aimed TOWARD the piece of paneling that's already nailed. Half of these nails get pointed DOWN and toward the previous panel, then the other half get pointed UP and toward the previous panel. In other words, every OTHER nail up and with the point closer to the previous panel than the head is, with the ones in between pointing DOWN and with the point STILL closer to the previous panel than the head is.

Crap, even I'm confused now, and I WROTE that... If anybody is confused about what I mean here, yell and I'll post a couple of drawings.

When placing multiple layers on the OUTSIDE of your building, I'd still strongly recommend using a thin bead of caulk in the corner created by the stud and panel, so that joint is hermetically sealed. The previous plan of "toenailing" above, will squeeze any extra caulk out of the joint as you finish doing the nailing -

As much as I'm addicted to nail guns ( I have two), in my experience you do NOT want to use them for sound-proof construction. My logic is:

The nail gun shoots the nail thru the panel and into the stud so fast, the inertia of the panel keeps the panel from being drawn up as tightly against the stud as it could be. Hammering by hand, although painful, has always given me a much tighter construction result. This might not be as true if you have a helper to help keep the panel tight against the surface - another thing that might make it OK to use a nail gun is if you use acoustic caulk on the studs (and on successive layers) Then it wouldn't matter as much that the panels aren't quite as tight against the studs as they would be if hand hammered. I'm still mulling this one over... Steve

Michael Jones · Post by **Michael Jones** » Mon Apr 14, 2003 1:24 pm

OK cool. Thanks for the link.
I have to agree with you about nail guns. I have one that I used for framing, and it works great for that. But when it comes to nailing panels, hand hammering, and "seating" the nail works best. Some nail guns can drive the nail in just a little too deep, and that kind of upsets the structural integerity of the panel.

Hand hammering can get tiring too though.
I broke my elbow a few years ago doing something that no 40+ year old man should be doing: I was roller blading! (I'm usually pretty good though) But anyway, all this hammering has re-inflicted that injury.
That, and my hands no longer look loke a pianist's hands! They look like a carpenter's.

knightfly · Post by **knightfly** » Mon Apr 14, 2003 1:49 pm

Man, if this fucking laptop screws with me one more time it's going out the window (the one it makes when it gets thrown though a wall) got a bug somewhere, either hardware or drivers, that every so often the mouse goes berserk, jumps around the screen, clicks on things, all by itself - total havoc... Oh well, guess I'll start over, crappola...

Found this on USG site

http://www.usgaction.com/HANDBOOK/chap4/AC_APP.html

Lotta good pix, including proper caulking techniques. It's part of the USG construction handbook.

Here's the page for their acoustical sealant - the links at the bottom are javascript so you'll have to use this link then click on them yourself.Once you do, you can save the PDF for future reference...

http://www.usg.com/Product_Index/_produ ... eenLink=10

Checking the MSDS, the stuff is no serious hazard unless you eat it, for all practical purposes. Comes in 29 0z tubes and 5 gallon buckets.

The photo and submittal sheet has some of the same illustrations as the construction handbook - definitely useful.

In a few days I hope to get some time to run down actual prices and sources for this stuff - when I do, I'll post it in the materals forum. Later... Steve

jazzman · Post by **jazzman** » Tue Apr 15, 2003 1:38 am

Also consider OSI brand 175 acoustical sealant:
http://www.osisealants.com/proseries/PS ... /sc175.htm

I bought 4 cases of it at a good price through a local distributor that OSI told me about and it seems to be fine.

Lee

liqdchris · Post by **liqdchris** » Tue Apr 15, 2003 9:00 am

Is caulk better than the can of sprayfoam you get from Home Depot/Lowes? I have several can's of sprayfoam, and am wondering if it's ok to fill any gaps with it, or if caulk would work better.

I know that caulk helps to stop vibrations, but is it better for helping sound isolation vs. the sprayfoam?

knightfly · Post by **knightfly** » Tue Apr 15, 2003 9:16 am

Yeah, the proper caulk is heavier-bodied and won't harden and shrink away from the surfaces. Makes a LOT of difference in wall performance. Here is a bit more info -

http://www.usgaction.com/HANDBOOK/chap4/AC_APP.html

liqdchris · Post by **liqdchris** » Tue Apr 15, 2003 9:36 am

Good link Steve. I read through the whole Owens Corning site as well.

So, do the cans of sprayfoam just act as thermal insulation, and no sound insulation/isolation? That's what I've been able to determine. I've read somewhere that styrofoam is a good conducter of sound so that would be bad to use.

I have about 5 cans of spray foam. Any ideas of where to use them?

(Neighbors tailpipe?) hhhehe

nah, I'm not that kind of guy. I'll head to Home Depot today and check out their wall of caulk to see if they have any decent acoustical caulk there.

knightfly · Post by **knightfly** » Tue Apr 15, 2003 9:56 am

Yeah, Chris, like the tailpipe idea :=) Seriously though, heat insulation and sound insulation are worlds apart. You could take a 10 foot square section of wall that's insulated to R-1 million, put a 1 square foot hole in it, and only lose 1% of your heat (unless there's a fan helping out) but a 1/16" crack 6 feet long in the same wall would lower it from STC 60 to STC 45 or so. That's why I made the comment in another thread about using cabinet maker tolerances and caulk.

I hope to get to the Home Depot "wall of caulk" aisle soon too, see what they have and do some research. This is getting as hard to nail down as the sources for 703 insulation... Steve

knightfly · Post by **knightfly** » Tue May 06, 2003 9:34 am

Minor update - if your Home Depot is as useless as my local one, forget receiving any help on acoustics - I checked with my local HD about a week ago, and found NOTHING... no usable acoustic caulk, they knew nothing about Resilient Channel, had NOTHING useable in the way of insulation (unless you just need "fuzzy stuff" for a particular application -

About the only useful stuff I found there, besides screws, was 5/8" firecode sheet rock at about $5.50 per 4x8 foot sheet.

Still looking... Steve

liqdchris · Post by **liqdchris** » Wed May 07, 2003 8:05 am

Yea, I live down the street from Home Depot. The guy in the caulking area said any of it would work and he handed me liquid nailz. I then went to the insullation department and they said to use egg crates. LoL They also said that the soundboard would stop the sound cause it said "Sound Stop" on it.

I found much more usefull information on the internet, and especially from this site. Thanks!!

knightfly · Post by **knightfly** » Wed May 07, 2003 11:01 am

Yeah, I used the egg crate thing on a wall behind my drummer about 16 years ago (before I knew there even WAS a difference between sound PROOF and in-room acoustics) - the good news is it actually WORKED for what I was mainly trying to do, we had a feedback prob at around 6.3k and it went away. About 3 months ago I came across a PDF of an actual test of egg crates, and guess where they PEAK (.7 absorption roughly) - you guessed it...

You can't really blame Home Depot guys for their ignorance - whenever I encounter lack of knowledge I (usually) try to remember back to when I put up those egg crates :=)

I'm not giving up on the materials thing (not my style) but have had zero time lately. One of my goals, both personally and for this forum, is to lock down sources for as many of these hard-to-find items in as many areas as I can - it won't be a quick project, but eventually I hope we can all spend less time being frustrated over the "vacuum" in some of the usable materials... Steve

knightfly · Post by **knightfly** » Sun May 25, 2003 4:30 am

Just an update -

After looking around some more, I've finally come to the conclusion that the best thing you can do for caulk is order the real thing from someone like these guys -

http://www.acousticalsolutions.com/prod ... /caulk.asp

Their price of $7.50 a tube doesn't seem like much when you consider that it's a 29 oz tube - the 10 oz tubes of regular stuff run anywhere from $3 to $5 (!!?!??)

Sooo, my recommendation (which I intend to follow) is to just find a contractor-size caulk gun locally (air actuated if you have an air compressor and can find such a gun) then, order at least twice the amount you think you'll need from the above site, or USG (I've not been able to find a net source for the USG yet) and get on with the program.

Considering the relatively low cost per unit of the REAL stuff, I'd definitely NOT take any short cuts... Steve

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