Is it possible to prevent one roof to cut into the first roof? For example to make a small roof over entrance that simply goes on top of the main roof, without changes in the main roof. Or maybe that the slices in main roof under entrance roof, down to OSB over rafters are cut away, but the rest stays.
[Blockierte Grafik: http://i744.photobucket.com/albums/xx81/Thorvald73/Building%20construction/Houseroofoverentrance.jpg]