trouble with roof

[Elovia]

Yo Dawg ...

Welcome to the forum. Which software title are you using to create your model?

I'm not clear on what you're trying to achieve with "one of the gables (on the left side of house) won't generate", but let me point you to the following help database article that might be what you're looking for:
http://www.homedesignersoftware.com/...?faqNumber=456

Another help database article you may want to read for the flatter pitched roof plane:
http://www.homedesignersoftware.com/...?faqNumber=871

Hope this helps.