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Residential truss bracing

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Thor Matteson wrote:

"The plated truss industry should take a hard look at how truss roofed
systems are _really_ constructed.  Passing the PLB buck to some phantom
"building designer" (that usually does not exist, in the case of
residential
trusses) does not help the homeowner whose roof has just collapsed."

I don't know that the industy's fear is just the expense of a few
dollars more per truss for real engineering.  I assume the fear is that
it won't be uniformly enforced, and the conscientious guy will get eaten
alive.  In residential construction, that fear is probably realistic.

For the record, I don't much like these trusses or their manufacturers.
The few times I've dealt with them, I've found them to be even more
difficult to work with than PEMB manufacturers.  The reasons are
probably the same--essentially a commodity product, in a low-bid
environment where everyone designs just barely to some standard, and
price is all that matters.  I've put notes in my drawings regarding snow
drift loading, bracing, engineering certification--they don't care.
They don't give a rat's ass.  They just ignore all that and sell what
they sell.  Consequently, they don't sell much of it on my projects.
But then, I don't do residential.

That said, there are an awful lot of those truuses out there, and I
don't hear of many collapses.  And this is largely on tract residential
work, where the contractors (many of them) are so speed-driven and
uncaring that we don't even want to know how things get built; and then
Harry Homeowner wants to make some storage space, so he removes "just a
few" of those pesky diagonals, or cuts the bottom chord to install a
stair.  Yet they don't fall down.

Like I said, I don't like them much--the manufacturers are frustrating
as hell to deal with.  But the question still needs to be asked: where's
the bodies?

Mike Hemstad, P.E.
TKDA
St. Paul, Minnesota

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