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Yesterday I called Unirac, and was told that the only time they had heard
of this issue before was when the trusses were made from glue lams.
They have heard no complaints of truss failures. I'm sure
installers would have let them know. <br><br>
We are planning to use 5/16" lags, which I doubt would be a
problem. I think our Truss mfg is being overly territorial.
<br><br>
-Drake <br><br>
<br>
At 03:28 PM 4/27/2010, you wrote:<br>
<blockquote type=cite class=cite cite="">Hi Drake and all,<br><br>
We have had both engineers and inspectors question the use of a 3/8"
4" lag in a 2x4 top chord and I think rightfully so. When we
have a chance to spec new construction we have the architect replace the
2x4 top chord with a 2x6.<br><br>
And when we have to go into 2x4's we either shorten our lag to a
5/16" 3.5" or even 3" (if we can get away with it on the
uplift calcs) so we stay in the top half of the wood fibers on the
truss. We have also sistered or blocked 2x4s when there was
concern.<br><br>
But like Bruce said - I cannot imagine there ever being a problem with a
2x6 with a 4 " lag (only 3.5" of which goes into the wood)
unless you were using 1/2" lags!<br><br>
The real issue is in installation. Installing a lag so that it
glances the side and splits the rafter or hitting a knot and not backing
off could cause problems. So we are really careful in installation
to make sure we are right on the center of the truss - we drill tiny
probes everytime - that's where the real issue is - once engineering is
happy of course.<br><br>
Hope that helps!<br><br>
Jeff Clearwater<br>
Village Power Design<br><br>
<br>
</blockquote>
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<font color="#0000FF">Drake Chamberlin<br>
Athens Electric<br>
OH License 44810<br>
CO License 3773<br>
NABCEP </font><font size=1 color="#0000FF">TM
</font><font color="#0000FF">Certified PV Installer <br>
Office - 740-448-7328<br>
Mobile - 740-856-9648 </font></body>
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