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RE: sound transmission, treated wood

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From what I've read, zinc borate has been shown to be non-corrosive to metal fasteners (borates comprise soap).  I don't think details have changed though; if you used a hot-dipped galvanized or stainless steel fastener before, you still use it with ZB.  Other popular options are ACQ, ACZA, and CA-B. That's by no means a complete list, and there are regional variations in what method(s) are commonly available.
 
The CCA alternatives do appear to be more corrosive to metal fasteners, particularly untreated/uncoated fasteners.  I've seen some varying reports regarding HDG and SS fasteners in treated wood, so I would just suggest to keep an open eye.  My initial opinion is that SS holds an edge in some treatments and performs similarly in others.  (BTW, Simpson Strong-Tie seems to agree (for now))
 
Going back to sound - it is certainly a science of its own, complete with people serving as experts in design and litigation - expensive experts at that.  I would hope that none of you are forced to act as the STC/IIC specifier as it does require some study.  However, if your work is of general office buildings or residences, you should be able to educate yourself enough over a weekend to be able to say if the wall or ceiling/floor system will be in the ballpark of  generally acceptable performance.  Typing "STC IIC" in a search engine will bring up thousands of documents on ratings for specific systems and commodity and proprietary enhancement products, plus some general information on how to install such things as resisient metal channels or staggering studs within a wall.  **Antecdotal note - one of my searches found a web site for growing marijuana.  Apparently this guy wanted to soundproof the room from the various lights and hydroponic devices he was using - the site actually was fairly useful (for sound transmission)
-----Original Message-----
From: Ed Tornberg [mailto:edt(--nospam--at)blazerind.com]
Sent: Thursday, December 18, 2003 4:21 PM
To: seaint(--nospam--at)seaint.org
Subject: RE: sound transmission, treated wood

I recently checked into this regarding buildings built for termite resistance (not rot).
 
All copper-based treatment products accelerate the corrosion of steel fasteners, but of course moisture must be present to support the process.  While it is true CA-B is more aggressive than CCA, it has always been the recommendation of fastener manufacturers to use HDG or SS.  (And note this is required by UBC 2304.3 anyway.)
 
The caveat is that for treated lumber that has a maintains a low moisture content, EG or even untreated fasteners may be okay.  But because there is no testing to my knowledge (and Simpson, when I queried them), no one will say in writing that this is acceptable. 
 
The bottom line is that there should be no change in specifying fasteners for CA-B treated lumber; as it has always been for CCA they should be HDG or SS (or silicon bronze or copper) unless you have a good reason (and no fear of litigation) to believe that something else will work.
 
A fast-growing option, especially for termite resistance, is borate-treatment, which is non-toxic.  I don't know what the fastener effect is.  The down-side of borates is that they leach out of wood that is subjected to water transmission, like ground contact.  Trus-Joist has tried selling it for sill plates in LSL material.
 
Ed Tornberg
-----Original Message-----
From: Andrew Kester [mailto:akester(--nospam--at)bbma.com]
Sent: Thursday, December 18, 2003 8:03 AM
To: seaint(--nospam--at)seaint.org
Subject: sound transmission, treated wood

IMO, sound transmission is a science unto its own, not one that should be tackled by SEs. I am working on a school project, and in the Music building they hired an acoustician to make such high tech reccomendations as solid grouted full height walls :)  There are special drop ceilings, foams to use at wall penetrations, etc., so there must be something to the science or else why would they spend taxpayers money on this consultant, right?
 
TREATED WOOD
CCA is being phased out as of Dec. 31st, 2003. So I was wondering what most of you plan on specifying for  treated wood ?  I have heard that the new preservatives can be much more corrosive, and that some fasteners may be required to be stainless or hot dip galv. Any thoughts or opinions would be welcomed.
 
Thanks,
 

Andrew kester

Longwood, FL