I am attempting a new project I am adding an additioinal 14'8" x 8' slab and want to put a lean to style roof over it, It will connect to a current porch that is 14' 8" x 6'6" porch. My question is how to tie it into the current roof? I am wanting to do as little demolition as possible to it. Considering either just removing molding and using face mount joist hanger, or tieing into the roof rafters (would rather not). Here are my initial ideas. 6" slab, (2) 4x4 support posts at each corner of slab, 2x6 rafters 24" apart same as current rafters on roof. 4x6 support beam, 19x32 plywood for roof, shingles to match roof.