I have a project where we're going to add some new roof joist on top of an existing roof
so we can add some insulation. The existing roof is the one of those Viceroy, Lindal,
Panabode style roofs with exposed beams and nominal 2" T&G Cedar that's left exposed
on the underside. So to add insulation we're building ontop of that. Anyway my question
is; what would be the best way to place a double roof on a building for 3D purposes.
Certainly for 2D I could just line draw what I needed and I guess for 3D I could just make
the rafters quite deep and the fascia wide with a shadow board, but just wondered if there
was a way to actually do the double roof right off the top ?