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Ripping Graded Lumber WAS: When is an Architect or Engineer Required?

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Chuck,
I would disagree with you IF the engineer or designer down grades the
lumber in his calculations. In other words, I've often preferred to rip
a 2x12 where a 2x10 or 2x8 might be all that is required if it
calculates out for a No.2 graded lumber when I would have specified a
No.1 or better originally. 
The reason for this decision is that most builders don't like the idea
of building up additional lumber above the structural roof in order to
slope for drainage a flat roof. Raising up the plate heights creates a
problem and increases the cost for a ceiling if separate ceiling joists
need to be installed and adding "Rip-strips" above the flat rafter
destroys the shear transfer unless you can control the quality of
construction to restore the shear transfer using Simpson Clips.

LSL and LVL lumber creates a much more expensive roof. The choice I
might use the most often is simply to have the roof designed for plated
roof trusses unless the span is short - then I stick to ripping the 2x's
to meet the slope and protect the structural sheathing shear transfer.

Dennis

-----Original Message-----
From: chuckuc [mailto:chuckuc(--nospam--at)pacbell.net] 
Sent: Thursday, July 17, 2003 9:46 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: When is an Architect or Engineer Required?


Dennis-
Ripping graded lumber is a highly dubious practice (unless you have it 
regraded when you're done).  Both the allowable knot size & the location

of the defects change. LSL & LVL shouldn't pose a problem, but I don't 
allow the ripping of sawn lumber with serious bending loads.
In Bill's case it sounded like the lower (shear diaphragm) was left 
intact & an upper drainage surface was being added above it.  It needs 
to be held down, but shear flow shouldn't be a problem.
C. Utzman,P.E.

Dennis Wish wrote:

>Bill,
>California laws for roofing differ from Texas and based on the 
>information you provide, you did exactly the right thing. I hope you 
>will keep us updated as to what you learn from the state's actions. The

>ripped 2x's that you describe are also used here to slope the roof for 
>drainage. I found that this creates a problem with shear transfer 
>through the diaphragm and in my projects either require the rafters to 
>be ripped to the appropriate slope or for the roofer to build up the 
>drainage above the structural sheathing. The purpose is to protect the 
>lateral load path whether it is due to wind or seismic. FWIW, Simpson 
>has a clip that to be used for such a purpose as you describe. It is 
>nailed to the face of the rafter and the ripped strip above to secure a

>lateral load path from the sheathing to the ripped 2x's and into the 
>rafters to the blocked bearing connections at the walls.
>I think you stated it very clearly and the state hopefully will do
their
>duty and act on your report.
>
>Dennis
>
>-----Original Message-----
>From: Bill Polhemus [mailto:bill(--nospam--at)polhemus.cc]
>Sent: Wednesday, July 16, 2003 4:30 AM
>To: seaint(--nospam--at)seaint.org
>Subject: RE: When is an Architect or Engineer Required?
>
>
>I thank you all for your responses.
>
>It seems to me that there are two "incriminating" facts here.
>
>First, this isn't just a "residential job." This is a complex of about 
>ten two-story buildings with from eight to sixteen residential units 
>each. State law requires an engineer if you have a multiple dwelling 
>with more than eight units. And the total contract amount was in excess

>of $600,000 dollars. State law requires an engineer if the project size

>exceeds $20,000.
>
>Second, they did not just remove the old built-up roof and replace it 
>with new roofing material. They came in an "scabbed" new, tapered 
>rafters on top of the existing roof deck and framing, and put down new 
>deck on top of that. These are structural elements, particularly here 
>where the design wind speed is 110 mph.
>
>The most egregious thing--at least to me, with my practical mind--is 
>that the "facility consultant" was supposed to provide construction 
>management, and they essentially did not. This isn't an "engineering 
>thing," solely, but it is indicative of the "furtive" nature of their 
>operation, at least to my mind. They didn't bother going for a 
>construction permit. This is the contractor's responsibility, normally,

>but the "consultant" should have seen to it that the permit was 
>secured, and not allowed the contractor to proceed without it. 
>Construction permits are required, even for re-roofing.
>
>Why did they not do this? One possible explanation is they didn't want 
>to call attantion to what they were doing. They wanted to pretend that 
>this was "just a reroofing job," and leave it at that. The contractor 
>kept insisting a permit wasn't needed for "re-roofing." Yet if it was 
>"just re-roofing," why did the "facility consultant" inform my client 
>that they had to provide a new, sloped roof in order to comply with the

>new building code? (And their advice wasn't even correct as it turned 
>out).
>
>The irony is, the spec the "consultant" put out was actually pretty 
>good--a lot better than many engineers I have seen. But they didn't 
>enforce their own bid document, and they didn't follow through with 
>proper construction management procedures. No Q.A., period.
>
>So there's the letter of the law, and the spirit. Both violated, IMO.
>
>FWIW, I have sent an email to the TBPE compliance office, and included 
>the bid documents (including the drawings showing the connection 
>detail,
>etc.) I have asked them to investigate and determine for themselves if
>the law was violated.
>
>It's going out on a limb, I know, but I am determined to blow the 
>whistle on this kind of stuff if ever I find it.
>
>-----Original Message-----
>From: Scott Maxwell [mailto:smaxwell(--nospam--at)engin.umich.edu]
>Sent: Wednesday, July 16, 2003 12:43 AM
>To: seaint(--nospam--at)seaint.org
>Subject: Re: When is an Architect or Engineer Required?
>
>To me, the "fishy" thing is the inclusion of the new
>tapered rafters.  Without out that, it would sound like a basic, good 
>ol' re-roofin' job,...
>
>
>
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