My project house is a 2story with a flat facade. I want to add a wraparound porch to dress it up. I plan to come out about 6 foot with the porch. How do I figure the pitch of the roof and how high it will be fastened to the 2nd story. I want to have a reference point where the roofline will be before I replace the 2nd story windows. i am sure they will be shorter than they are now???