Building an internal truss system to raise a ceiling?

[db987654]

Hello,
I am in the process of renovating my home and want to raise the ceiling within a gable frame 2.5 feet (drawing is attached). The present construction is traditional (joists/rafters/ridge beam) but no collar ties. I want to essentially move the joist up 2.5 feet (making them collar ties essentially) and build the necessary other structural members within the attic as opposed to removing the entire roof and installing engineered trusses & reroofing. The sketch includes my initial (UN-analyzed) thoughts to a successful system. Does anyone have any thoughts / answers for me? Snow load in my state is 50#.

Thanks

 

[BAretired]

Hire a structural engineer to analyze your proposed system or make recommendations on how to accomplish your goal. I suspect that your idea as sketched will need some revision.

BA

 

[ameyerrenke]

+1 to BAretired's response. Likely a doable project, but have a structural take a look at it, he'll probably save you enough in materials vs. your own analysis to pay for himself anyway.

 

[Archie264]

...especially since it appears to be a 50 psf snow zone.