GeneDavis

Forced truss rebuild won't go to raised roof

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I have a complex trussed roof arrangement done and worked with the truss builder's engineer to figure out the scheme, then built the scheme into my Chief model.

 

Then he comes back at me after he runs the loads (92 psf ground snow) and says we need two inches more heel height, up to 9.5 inches from the 7.5 we had when I built all the trusses.  I know, 7.5 seems light for a place where you have all the snow but we're going to foam the roof.

 

Anyhow, I choose a truss and do a forced rebuild, after I have raised the roof, and the truss top chords don't jump up to the raised roof.  Why not?  It's going to be a lot of work drawing all new trusses.

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Before you rebuild all your trusses, I would address the need for an energy heel in the truss design.  With a snow load that you mentioned, you would need a 14" energy heel so the insulation does not need to be compacted down to fit inside your 9.5" space.  This is pretty common practice in areas with snow.

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You saw the word "foam," right?  Unvented roof, conditioned attic space, 7 inches closed-cell foam against underside of deck.

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Bit of a guessing game without the Plan......

 

did you try rebuilding the roof Framing after raising it up the two inches? Needed not sure? 

 

Chief needs a Ceiling plane and a Roof plane, to build trusses, so maybe a cross section will let you see what is going on

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Find my earlier thread of 48 hours ago, wall junction edit.  That's the plan.

 

i went ALL OFF, turned on all roof planes, baselines, ridge caps, moved all up 2".

 

Then got stumped when force rebuild wouldn't do as expected.

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Have you manually changed the truss?

 

Make sure this is not checked.

 

ct1.thumb.png.8e1c71f0d7f24b9598f639cde604eca1.png

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I've no Chief for a bit, but no, I did not try s new one right alongside.

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1 hour ago, GeneDavis said:

i went ALL OFF, turned on all roof planes, baselines, ridge caps, moved all up 2".

 

Then got stumped when force rebuild wouldn't do as expected.

 

That would have been a transform and Replicate move ?   I think I remember having issues with that last time I did it.

 

Give Edit All Roof Planes a try.

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My action raised the roof planes as expected.  Should I not have raised the baselines?  Is that my problem?

 

Do baselines even HAVE an elevation?

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I am thinking that ridge caps and baselines should move by moving only the roof planes but would need to run a controlled test to be sure.

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1 hour ago, GeneDavis said:

Find my earlier thread of 48 hours ago, wall junction edit.  That's the plan.

 

 

How about stripping that plan down so it's smaller and posting the current version.

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@GeneDavis

Zip that sucker up and post the plan. You'll have answers in no time. How many trusses are in your model? I've experienced something similar but only with floor trusses, never roof trusses. I believe it was because there were too many for Chief. Tech Support had no answers.

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Gene,  I just tried a +2" Z Transformation of all of your roof planes on the previously posted plan file and the trusses seem to be responding correctly to a Forced Rebuild.  Was there a particular truss that was giving issues or a particular roof plane ?

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219969567_BaselingHeight2.thumb.PNG.c56c612499784bd5c272fcc650bca951.PNG

7 hours ago, GeneDavis said:

My action raised the roof planes as expected.  Should I not have raised the baselines?  Is that my problem?

 

Do baselines even HAVE an elevation?

 

When you raise your roof plane, the baseline would have to raise as it is on the top of 

the roof plane (rafter or top cord, not sheathing)

 

Baseline elevation, or height is in the roof plane dbx.  

 

In the drawing you can see it is the sum of the wall frame, and the vertical measurement

from the outside top of wall to top of rafter.

 

Baseling Height 2.PNG

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OK I am back with Chief and can say that truss rebuild works fine for an untouched truss after raising the roof (and baselines) 2".

 

The issue was with a truss I had edited the tails on, and maybe had jiggled the top chord somehow to maybe fix it?  That truss would not rebuild as expected, so I deleted it, placed a new one and it generated as expected.

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