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Plywood Sheathing - Cautionary Tale

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Dear All;

Something to be aware of during construction.

Our office did a 3 phase remodel/addition  at a local private school.
During the 3rd phase (addition/remodel) to an existing 2 story building
(basement/upper level with the upper level basically being wood
framed).  During an inspection of the roof sheathing, I noticed the
plywood grade stamp did not mention the American Plywood Association
(APA).  I told the contractor to ask his framer what was going on.
After some period of time, and after the roofing was in place, I had not
gotten a satisfactory answer to the question.  Talking to Russ Shimer of
the APA, he asked me to fax a copy of the grade stamp which I had
photographed.  I did so, and he called back, saying that we had a  piece
of plywood graded by a private lab.  Upon contacting the lab to find out
what the grade of the plywood, I received a copy of a page out the 1997
UBC with a penciled arrow indicating the span index of the plywood
(which was on the stamp); I called back and asked what the diaphragm
values were.  Again, came another xeroxed page out of the UBC, with
penciled arrow annotation saying it was just like CDX (Struct II).  We
had specified Struct I plywood but luckily the shear values were not all
that high and the Struct II values worked.  The contractor's
superintendent says he has pictures showing the majority of the roof
sheathing with the APA stamp, have not seen them but the roof is up 15'
or so in the air and very dark during construction, so any picture would
be worthless.  The framer says the oddball sheets were accidentally put
in by the supply house, I don't know.  APA stamped plywood was used on
the shear walls.

Russ Shimer said that plywood is now a commodity construction item, and
some people feel the APA inspection fees are too high and offer an
alternative inspection service.  Based on the level of professional data
provided by the lab plus no name just a logo which Russ S. had to
identify for me, I would not get any warm fuzzies on a larger job, with
APA Struct I plywood called out and reasonably large diaphragm loads.

Just something else to keep an eye out for.

Patrick Rodgers