GeneDavis Posted October 7, 2019 Share Posted October 7, 2019 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. Link to comment Share on other sites More sharing options...
javatom Posted October 7, 2019 Share Posted October 7, 2019 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. Link to comment Share on other sites More sharing options...
GeneDavis Posted October 7, 2019 Author Share Posted October 7, 2019 You saw the word "foam," right? Unvented roof, conditioned attic space, 7 inches closed-cell foam against underside of deck. Link to comment Share on other sites More sharing options...
Kbird1 Posted October 7, 2019 Share Posted October 7, 2019 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 Link to comment Share on other sites More sharing options...
GeneDavis Posted October 7, 2019 Author Share Posted October 7, 2019 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. Link to comment Share on other sites More sharing options...
GeneDavis Posted October 7, 2019 Author Share Posted October 7, 2019 Unlocked, yes. Link to comment Share on other sites More sharing options...
GeneDavis Posted October 7, 2019 Author Share Posted October 7, 2019 I've no Chief for a bit, but no, I did not try s new one right alongside. Link to comment Share on other sites More sharing options...
Chopsaw Posted October 7, 2019 Share Posted October 7, 2019 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. Link to comment Share on other sites More sharing options...
GeneDavis Posted October 7, 2019 Author Share Posted October 7, 2019 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? Link to comment Share on other sites More sharing options...
Chopsaw Posted October 7, 2019 Share Posted October 7, 2019 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. Link to comment Share on other sites More sharing options...
robdyck Posted October 7, 2019 Share Posted October 7, 2019 @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. Link to comment Share on other sites More sharing options...
Chopsaw Posted October 8, 2019 Share Posted October 8, 2019 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 ? Link to comment Share on other sites More sharing options...
GeneDavis Posted October 8, 2019 Author Share Posted October 8, 2019 Tx, Chop. I'll get back to it tomorrow nite and report. Link to comment Share on other sites More sharing options...
JJohnson Posted October 8, 2019 Share Posted October 8, 2019 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. Link to comment Share on other sites More sharing options...
GeneDavis Posted October 8, 2019 Author Share Posted October 8, 2019 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. Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now