I have been talking to someone concerning the Therma Save Sip panel. I submitted my house plans to have the panel drawings produced and the in the final drawings panels are not staggered. Is this typical?  These panel are extremely heavy. Each 4x12 roof panel weighs about 350lbs. Why would the panels not be staggered.


  Has anyone had any experiece with Green Sip? I believe they recently took over Hoots manufacting operation.

I would guess there are structural members (dbl 2xs, or LVLs) in the panel joints that run from eve to ridge? Unless you are using purlins, in that case I am all wet :)

If the non staggered joint bothers you then use a panel that is continuous

Just as one staggers CMU or brick, best building practice when laying panels on a roof would require that they would be staggered.  For example if you have a 6 foot rafter span across a 48ft roof you would lay four 12ft panels across first (eave) run and then intersperse the second run with a two 6ft panels and three 12ft panels.  This would stagger the panels across the rafters in a "brick" pattern.  Problem comes when the span capabilities of your panels do not coincide with the rafter/beam spacing of your design.  If your rafter spacing in this design is 10-12ft, and they do not manufacture a 20-24ft panel (to provide an offset), then I can easily see why they would be forced to give you a layup design with no offset.

I suggest you simply ask them why there is no offset.  Sometimes designers have a pretty good reason, it's just not obvious to the uninformed.

CHL;

one of the obvious reasons that sticks out to me is: if you stagger the joints then you also need additional beams to stagger them on, instead on one intermediate beam now you will need 3 just for the sake of staggering panel joints is not a cost effective design idea

Yes, as I stated above it all depends on the nature of the design and the capabilities of the panels under review.  You will get a stronger structure by interspersing panels (just like in laying block or brick) but this might not be possible if they are looking for a large span for aesthetic or architectural reasons. 

There is a reason that bricks are staggered, and a reason that even 4x8 roof sheathing on a traditional framed roof are layed up in a staggered pattern - they've learned that over time long knit joints will telegraph.  While the inside surface of a sip panel should remain fairly uniform in temperature the outside surface temp will vary wildly, and environmental conditions can be adverse.  For this reason you do not want to always maximize your panel span - this isn't about "who's panel can span the longest", it's about sound design principles.

You may well have a point in SOME DESIGNS, especially small ones.  But as the size of the roof diaphragm grows it simply doesn't make sense to skimp on structure just so you can maximize the capabilities of your panel span in order to save some dollars in the cost of additional beams.

Plywood is staggered because it is not practical to manufacture or handle in long lengths.
If you think back before plywood ...1 x sheathing was run in longer lengths because it was available.
Joints are the weak point of  construction materials and should be avoided if possible and practical.

Sound building designs avoid splicing materials

less joints = less telegraphing

Uh, seriously, this makes no sense.  The presence of a stagger has very little to do with the dimension of the materials - in fact framers today are going out of their way (cutting materials) to establish the offset.  Think about it - wouldn't they be lining the panels up like you are suggesting - with no stagger - if this was a better way to do it?  There would be less cutting of materials and that's ALWAYS a good thing, right?  Hint: the answer is no.  It has everything to do with span, the materials you're using and good design principles.

Your argument about roof panel seams doesn't make much sense either.  I hope you're using an overlay material on your panel roofs and not relying on the joint itself (either end joint or edge joint)- it is strongly recommended.

CHL;

what are your qualifications to be making these statements?