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RE: Dry Lumber

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Roger,
This was, essentially my response to a later e-mail from Nels. For those
who wonder why: There are fewer mountains and a much drier climate in
Southeastern California (Riverside, San Bernardino and Imperial
Counties). The western half of San Bernardino and Riverside Counties lie
on the West side of the San Jacinto mountains which pick up the moisture
and climate from the coastal regions. However, once  you travel over to
the east side of the mountains you are in the Mojave desert and
essentially at the southern tip of Death Valley. Rainfall in this area
is less than an inch or two per year and the last heavy rain we had was
ten years ago when I had to delay the construction of my home due to
almost a month of constant rain. This was very unusual as a typical rain
in our area is considered a ten minute light shower that stops almost as
quickly as it started. 
Arizona is a Sonoran Desert - subject to a summer monsoon that brings
moisture from the Gulf of Mexico and from over the Mexican border.
Phoenix is drier than Tucson, but still receives heavy rain during the
summer months. The rains, and flash floods occur in this basin area that
extends up to Salt Lake City (which is one reason why July is the most
serious month not to be caught in a narrow canyon - flash flooding is
common.
Also there are more mountain ranges (especially traveling up from Tucson
to Northern Arizona through Show Low, Payson, Snowflake and finally into
the Navajo reservation which is at the higher elevations. 

In short, Roger is correct - the moisture content of the wood after it
leaves the plant can change by the time it is used and again by the time
sheathing and finish is applied. It is difficult to insure consistent
moisture content. I suspect that Vegas might be similar as it lies in
the same geotechnical region that was, at one time, the great ocean and
this extends between the Sierra Nevada's and the Rocky Mountains.

Finally, I think that it would be much easier to specify kiln dried and
find more consistency here in the Mojave Desert than in the Sonoran
regions of Arizona. 

I have given Nels a link to A.C. Houston Lumber in Vegas who also has or
had a lumber yard in the Coachella Valley. For those interested the link
is: http://www.achoustonlumber.com/about_us.htm

Regards,
Dennis

-----Original Message-----
From: Roger Turk [mailto:73527.1356(--nospam--at)compuserve.com] 
Sent: Sunday, September 28, 2003 10:42 AM
To: seaint(--nospam--at)seaint.org
Subject: RE: Dry Lumber


Dennis Wish wrote:

. > Roger Turk in Tucson has more rain in his area and greater humidity
that 
. > we have in the Mojave Desert (he is in a Sonorian Desert) but I
think he . > designs mostly with kiln dried lumber as well.

Hi Dennis,

Since it has only been relatively recently that a limiting moisture
content 
has been specified for kiln dry lumber other than by the Southern Pine 
Inspection Bureau, no, I don't specify kiln dry lumber because the
chance of 
getting it in all of your pieces is as good as finding a snowball in
hell.  
With current grading rules, kiln dry lumber, IIRC, has to have less than
12 
percent moisture *when graded* and could have considerably more when it 
arrives on site.

I specify that the lumber be graded "dry" and hope that it was not
subject to 
rain or snow while being transported or stockpiled.  "Everybody" knows
that 
it doesn't rain in the desert southwest (even during the summer rainy 
season), so lumber is stockpiled on site without protection.
"Everybody" 
knows it won't rain overnight, so structures are not dried-in at the end
of 
work each day, regardless of what the specifications may say.  It is
rare to 
even see stockpiled lumber on site stickered.

If a client wants pieces larger than 4 X 12's, I make them aware in
writing 
that the piece is subject to splitting, checking, shakes, warping,
cupping, 
twisting and just about every other visually bad thing that can happen
to 
lumber.

A. Roger Turk, P.E.(Structural)
Tucson, Arizona

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