Draw roof with no 0° pitch. In type properties set layer 2 to variable, then use Shape Editnig Tools and adjust points for fall,

Edit

Sorry missed the line
"we need layers 3&4 to remain constanly sloping"

my bad.....

It will take 2 roofs to do it, unfortunately. The entire uniform sloped roof can be one, and one with a variable thickness on top of it with join geometry done to mesh the two together.

I run into this problem 90% of the roofs that I use. Unfortunatly they won't always join if something isn't quite lined up right and even when they do the material patterns can get messed up. I usually end adding a filled region over the cricket areas in the details to make it look nice.

This is the method I use.

Am I loosign my mind here. I am trying to get this to work and I am not having much success. I have a low sloped roof. The main roof is just the deck and I drew it with zero slope and then modified the elevations of the points to get it where I wanted. I then make a second roof type (which comprises the insuation and the protection board, the insulation is set to be variable) and draw it also with zero slope and when I edit the points, it does not act as I suspect, all the plus and minus is based ont he orginal plan that it was place as, whcih was flat.

What I am after is this...i have a sturtcural deck and 6" of insullation. on top of that 6" I want to place crickets and such. What am I missign and is this doable. The situation in concept is identical to the third picture fromt he orivial poster.

Also, just to be sure...I am not able to edit the point of th eroof is I give it any slope lines in the sketch...correct?

Thanks,
Drew