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Re: Question on wood Roof Trusses

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I have had to furnish plate data for trusses and did not have trouble
the data which was an ICBO ER report.

Stan Scholl, P.E.

On Sat, 13 Jan 2001 12:14:17 -0800 "Structuralist" <dennis.wish(--nospam--at)>
> George,
> One issue with your explanation that I happen to agree with. It is 
> not
> possible for an engineer to design the connections of a plated truss 
> without
> the design information on the specific truss plate used. This 
> information is
> protected as proprietary information by the different Plate 
> company's and is
> not available to the EOR. If you ask Alpine Truss for their plate 
> data so
> you can design the truss in your office with the intention of 
> producing a
> job-built truss or to take to other lumber yards to manufacture, you 
> will
> not get it. They work with specific software developers like Keymark
> Industries who create the truss program and then license it to 
> lumber yards
> who produce trusses using the proprietary press plates.
> Truss fabrication is a highly competitive industry - especially here 
> in the
> desert. When I left Los Angeles eight years ago, I had a custom home 
> which I
> wanted to design with trusses. I was only able to find one company 
> in
> Ventura county at the time who would provide the trusses, including 
> the
> design. When I arrived in the desert, I felt like an apprentice 
> again when I
> discovered that virtually every home was constructed with trusses. 
> In fact,
> in the last eight years, I am working on my first home that was 
> constructed
> using stacked lumber and I simply can not see how the designer 
> justified the
> cost. I have, admittedly, gained a tremendous respect for plated 
> trusses.
> There is no question that engineers or inspectors (especially on
> conventionally framed homes) need to have a keen eye to identify the
> defects, but to protect the trusses from unauthorized and dangerous
> modifications by contractors in the field.
> I remember a number of homes where the contractor nailed braces for 
> soffits
> to the bottom chord of the truss at plate locations effectively 
> splitting
> the lower chord. I've seen trusses stored on top of homes laid 
> upright at an
> angle supported to stud walls with 2x4 braces until the trusses 
> could be
> distributed and set permanently in place (a technique that will warp 
> and
> possibly damage the trusses). I've seen struts cut to allow for 
> mechanical
> ducts to pass and the inspectors had not caught the problem. There 
> are a
> number of possible field abuses.
> Most of my point is that the truss is proprietary and it is next to
> impossible for an engineer to design a plated trusses without the
> proprietary information that the manufacturer protects. Until this 
> changes,
> there is little we can do other than act as the EOR of the project 
> and
> distance ourselves as much as possible from possible problems with 
> the
> system that we can not anticipate without the proprietary 
> information.
> I don't add for truss review to my contract, but then again, I don't 
> reduce
> my fee because a client wishes to use trusses over having me design 
> the
> roof. I figure, that the time I save in the design I pick up in the
> coordination and responsibility as the EOR. So far no client has 
> complained
> about this.
> Dennis S. Wish, PE
> -----Original Message-----
> From: George Richards, P.E. [mailto:george(--nospam--at)]
> Sent: Saturday, January 13, 2001 10:23 AM
> To: 'seaint(--nospam--at)'
> Subject: RE: Question on wood Roof Trusses
> We do not view the truss designs that we review as inherently 
> incomplete.
> The designs we review generally conform to TPI standards and to our
> drawings.  As EOR we are responsible for the performance of the 
> structure.
> As EOR we could design the trusses ourselves and provide 
> construction
> documents showing how the trusses are to be built.  However, 
> industry
> practice is to allow the trusses to be design-built with the design 
> by a
> Specialty Engineer.  So then what defines exactly what the specialty
> engineer will do and what will we do?  First, there is a TPI 
> document
> defining our respective responsibilities.  Second there are the 
> project
> specifications (on our drawings) which further define our 
> responsibilities.
> The Specialty engineers designs the trusses themselves and truss to 
> truss
> connections.  We design the braces.  The proprietary of the product 
> is the
> trusses themselves.  They got stuck with the hangers because they 
> are in the
> best position to design the hangers.  The rest is ours unless we
> specifically define otherwise in the construction documents.  I am 
> not
> saying this is the best way, right way, or moral way.  This is in 
> general
> what the industry practice is and this is how we do our work.  The 
> client is
> not paying extra.  He is not paying us to design the trusses. He is 
> paying
> for a responsible person to assure that his structure is being built
> correctly and to keep the design-build vender, who gets the job 
> based on
> lowest price, honest.
> BTW our fee always includes as part of the base price one truss 
> review.  We
> have assigned part of the design to the structure to another 
> engineer.  How
> do we know that he likely followed our design intent unless we look 
> at his
> work?
> Respectfully, George Richards, P. E.
> -----Original Message-----
> From: Roger Turk [mailto:73527.1356(--nospam--at)]
> Sent: Saturday, January 13, 2001 9:39 AM
> To: seaint(--nospam--at)
> Subject: RE: Question on wood Roof Trusses
> George Richards wrote:
> >>I second Mr. Moore's opinion.  Our plans (for houses, not even 
> commercial)
> require that we review the roof truss drawings for conformance with 
> our
> design intent.  Over 90% of our builders do send us the drawings for 
> review
> prior to fabrication. The truss drawings are then forwarded to the 
> Building
> Official so that he can approve them.  This is in accordance with 
> the UBC
> section on deferred submittals. The Clients know up front that this 
> is the
> process and they pay for the service.  What the get is a safer home 
> more
> likely to be free of defects in design and construction.<<
> Why should the client pay for an incomplete design of a proprietary 
> product
> and then pay the EOR extra to complete the design?
> A. Roger Turk, P.E.(Structural)
> Tucson, Arizona