RAM Gable Roof Modeling

I am trying to model a gable roof.  I understand that this needs to be accomplished by adjusting the heights of the ridge beam but am having trouble defining two separate slab polygons.  I am able to successfully model one half of the gable roof and have it display correctly in 3D, but when I draw the opposite side of the roof slab edge the slab edge along the ridge beam for the first half disappears.  How can I successfully draw the 2 sides of the gable roof?  Thank you in advance.