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RE: Out of Plumb Trusses

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In case it may be helpful, here is some information you may not have on
ANSI/TPI 1-1995
5.2.1	Trusses shall not be installed with an overall bow or bow in any chord
or panel which exceeds the lesser of L/200 or two inches (x 25.4 for mm).  L
is the span of the truss or chord or panel length in inches or mm.

5.2.2	Trusses shall not be installed with a variation from plumb (vertical
tolerance) at any point along the length of the truss from top to bottom
chords which exceeds 1/50 of the depth of the truss at that point (D/50) or
two inches (x 25.4 for mm), whichever is less. This specification does not
apply to trusses specifically designed to be installed out of plumb.

5.2.3	Location of trusses along the bearing support shall be within 1/4 inch
(x 25.4 for mm) of plan dimensions.  Special hangers or supports shall be
located to support trusses within 1/4 inch (x 25.4 for mm) of plan
dimensions.  Trusses shall be located at the on-center spacing specified by
the truss drawing.

Hope this helps.

Ed Fasula

> -----Original Message-----
> From: Robert Fennema, P.E. [mailto:bobfennema(--nospam--at)]
> Sent: August 31, 1999 8:22 AM
> To: seaint(--nospam--at)
> Subject: Out of Plumb Trusses
> I have a client who is considering the purchase of a 60 odd unit
> apartment complex. There are six buildings all two story.  They were
> complete in 1984.  When inspecting the roof framing, I found several
> dozen trusses that are out of plumb. I found panel points up
> to 5 inches
> off center. There are also top chords that are misaligned
> between panel
> points.  The truss span 48 feet and have an intermediate support point
> at the mid span over the partition between the units.  The roof
> sheathing is 1/2 plywood.  The lower chords are supported by gypsum
> drywall on resilient channels.
> I am convinced that the rooof framing has not moved as the these
> conditions are random.  In some cases a truss will lean east while the
> adjacent one leans west.
> According to the City records, the tusses were designed by
> Truswal but I
> do not know the local supplier.
> How can I evaluate the significance of these conditions?  How
> can these
> conditions be repaired since removing the roof sheating is not very
> practical?