From: Charles Greenlaw <cgreenlaw(--nospam--at)speedlink.com>
Date: Mon, 21 Jun 1999 23:37:52 -0700
At 01:46 AM 6/21/99 EDT, Ray Shreenan wrote:
>I am an expert witness for the defense (the framer) in a law suit involving
>structural defects in a large housing tract. The plaintiff's structural
>listed as one of the defects, the nailing of plywood shear walls with box
>nails. I pulled nails out of several walls in several units and they were
>all box nails.
C.G.- Ray, thanks for clarifying. I just had to use the occasion to tell
some stories about a certain aspect of expert work that might have been the
case for you, but isn't. It will be for others; some will be on the
Design Professionals Insurance Co (DPIC) in Oakland CA sells a little
pamphlet for $5.00 that discusses expert work. ASFE Inc. (Am. Soil and
Foundation Engineers?) has an excellent 47-page guide to expert witness
work. I recommend both.
Plaintiff's (and cross-complainant's) engineer experts often claim the most
outlandish, preposterous deficiencies in routinely accepted construction
practices. Maybe here, too. There is a lot of bluff, bluster, and
intimidation in litigation tactics. You have to use a good "crap detector"
when on the defense side of it.
So the nails are "box" nails. So what? What authority establishes that they
should have been otherwise? Are box nails an honest mistake, or under the
circumstances no mistake at all?
>The plans as previously stated made no mention of common nails in the shear
>wall schedule or in the general notes on the structural detail sheets. The
>structural calcs were done using full values for common nails in the 1985 and
>1988 U.B.C plywood shear wall tables.
Right, but those tables listed galvanized box nails as having the same
values, clear into the 1991 UBC. Any mistake is in the UBC itself, corrected
for the 1994 edition. I wouldn't call substantial compliance with the 88 UBC
edition in effect (and also with an impending new 91 edition) a mistake on
You ask, > Was it common knowledge for
>framing contractors to use common nails for plywood shear wall nailing during
>that construction period (1989-1990)? I gather from your response that you
>felt that they should have known or that were knowledgeable of the building
>code's requirement for them.
On the contrary, I deny that there was a building code requirement for
common nails for shear wall nailing back then, or that a framer "should"
have chosen commons, given the discretion he was allowed to choose
otherwise. I get a lot of my work from reputable and conscientious
contractors and framers in my area, and they are very clear that they detest
using common nails. One of the best of these contractors, who is also a
suberb architect, insists that they would rather drive two sinker nails than
one common nail. The others agree. The reason primarily is the framing
lumber splitting. At the nail seminar by Chuck Shubnell that I mentioned
initially on this thread, he agreed that splitting is a big problem with the
thicker nails, even though there are fewer of them. I find framers don't
care how many nails I want, so long as the framing isn't damaged or at risk
My grandfather held Calif SE license no.25, and was a framer and expert
woodworker as well. He told me that the most valuable skill I could have as
an engineer was a good knowledge of construction. I deny I have that yet, so
I keep on listening to construction people. They appreciate it, and keep on
It is conceivable that a plaintiff expert could allege that it is a defect
to use common nails when box nails were allowed by code and by the drawings,
on grounds commons split and ruin the framing as soon as full load hits the
seasoned and shrunken lumber, if not immediately. It happened at Northridge
that super-strong welded connections split open, while softer, bolted and
riveted clip-angle connections of the old style did not. So too with common
nails in today's lousy lumber?
I design for the nail types favored by the people who use them, and who have
to contend with nailing's effects in real-world lumber. That means I design
for the diameter and length to be used, not for the word "common" as though
it was a magic pedigree. At a SEAOC Code committee meeting two summers ago,
when I was a proxy delegate from Central Section, I tried to interest the
other sections' delegates in an amended standard nailing table for 2000IBC
that would use the builder-favored nails (sinkers, etc.) in revised
quantities as an alternative to the table using commons almost exclusively.
It went over like I'd released a skunk under the table. The reasons given to
only allow commons reminded me of my emphysemic mother's reasons for
continuing to smoke.
It appears I'm not a true believer in the common nail gospel and don't
belong in the same tent with our reborn framing code experts.
>My experience has been that if you did not specify common nails you would get
>box nails. I know some engineers that would design using box nails with
>reduced values for plywood shear walls. In that circumstance the contractor
>would have no idea that there was a problem using them on some other job
>unless common nails were specified.
>My original query based on this information was meant to be whether or not it
>is fair for the framer to accept full responsibility for this problem.
As I have said and cited authority for it, framers have a duty to know trade
accepted standards for good workmanship, and to know building code that
pertains to what they have been allowed discretion over. And they have a
third duty, to follow the engineer's plans and specs. [B&P Code sec
7109(b).] The engineer said use the table, and the table gives a choice.
The contractor did choose. Hindsight says the choice is not what a much
later code edition would have allowed. So the contractor is neither a mind
reader nor a forecaster of future code revisions, but that is not a breach
of any duty one expects of contractors.
As for treading lightly, I suggest making sure your expertise is well
rounded out in the whole area of concern, and then assert your opinions
strongly and persistently.
Charles O. Greenlaw, SE Sacramento CA