Addition for a Duplex

[James Edwards]

Hey guys,

Currently evaluating turning  house into a duplex. The proposed area an addition would be added is where an old deck exists and will need replaced. The issue is the house has varying degrees of roof pitches and I am having a hard time picturing how it would be done. 

Basically, looking to build to the right of the picture view, where an existing deck is. Appx 500 sq feet. 

Don't mind the pine needles they were cleaned off.