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RE: PPT Lumber: Know What You're Buying

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Jordan,
I also posted Frank's e-mail (with his permission) on the Structuralist.Net
Professional Blog and embedded the link to the on-line magazine
"Professional Deck Builder" article. I did not check to see if it was posted
as a PDF file or if it is embedded into a web page - but the link is on our
Blog. 
Here is the link to Frank's Blog:
http://www.structuralist.net/wp_professional/index.php?cat=6


Regards,
Dennis S. Wish, PE
California Professional Engineer
Join our Free Topic Specific e-Mail Discussions at: 
http://www.structuralist.net
 
-----Original Message-----
From: Jordan Truesdell, PE [mailto:seaint(--nospam--at)truesdellengineering.com] 
Sent: Thursday, December 02, 2004 5:40 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: PPT Lumber: Know What You're Buying

Frank,

I don't suppose you could put a PDF link up on the VT website? There has 
been fairly little quantitative information in the mainstream literature 
about the use of the new treated woods. Most everything I've seen is 
gloom-and-doom about fasteners, and no real summary about old-to-new 
equivalents for specifying PT woods.  I'll admit I've paid less attention 
to the level of treatment, and more to the fasteners.

Have you talked with Cathy Cook at the town of Blacksburg about the 
disparity in ground treatment vs. above ground in the local materials?  I 
know that she and her staff are usually right on top of the code, but 
sometimes distinctions this fine (or, perhaps, this poorly publicized) can 
slip by.

Jordan
(soon to be in Blacksburg...if I can ever get my new office finished!)

At 12:20 PM 12/1/2004 -0500, you wrote:
>Most discussions about the transition to new preservative treatments have
>focused on the fact that the new treatments are more corrosive to metal
>fasteners in laboratory tests, and thus hot-dipped galvanized or stainless
>steel fasteners and connectors are recommended by the lumber industry.
>Another change that we have noticed in our area of Southwest Virginia, as
>well as spot checks in other areas, is the chemical retention levels.
>
>One surprising issue being overlooked is that 0.40 no longer means "Ground
>Contact" for all commonly used treatment chemicals.  For example, with the
>CA-B preservative, 0.10 pcf is "Above Ground" and 0.21 pcf is "Ground
>Contact."
>
>For a couple of decades prior to 2004, the PPT southern pine lumber that
was
>readily available in local supply stores was 0.40 pcf CCA (Ground Contact).
>Therefore, our opinions and observations on the excellent durability of PPT
>southern pine are based on "Ground Contact" chemical retentions.  "Above
>Ground" treatments for 2x_ dimension lumber were rarely seen in our area in
>the past, although it was supposedly available.  Now the new chemical
>preservatives are available in a variety of retention levels, some of which
>may be "code conforming" but may not yield the desired service life for
>critical structural components in a residential deck.  For example, a deck
>ledger attached to a house-band-joist is similar to a "Ground Contact"
>application because of the water trapping joints created and the likely
>accumulation of debris, dirt, and soil.  Assuming that only "Above Ground"
>2x_ is available in the retail stores, it is extremely likely that "Above
>Ground" material will be used for deck ledgers. At least in our area,
almost
>all of the 2x_ dimension lumber we have purchased has been 0.10 CA-B which
>is an "Above Ground" product.  This site (SEAINT) may be a good place to
>share what type of treatment is being used in your area for 2x_ material.
>End tags should contain the chemical treatment and retention level.
>
>Dr. Joe Loferski and I have published a paper on this subject in the
>Professional Deck Builder magazine. If you would like a copy, please send a
>self-addressed stamped envelope (one stamp) to me:
>Frank Woeste
>1502 Nelson Street
>Blacksburg, VA 24060
>and I will send you the paper. By the way, subscriptions to Professional
>Deck Builder magazine are free (www.deckmagazine.com/).
>
>Thanks, Frank Woeste
>Frank Woeste, Ph.D., P.E.
>Professor Emeritus, Virginia Tech
>Our next short course is:
>Design of Code Conforming Decks and Inspection of Existing Decks
>February 1-2, 2005 in Tampa, FL.  For details, visit:
>www.deckexpo.com/success_seminar.html
>
>
>
>
>
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