flat roof to pitched roof

[Cindy Joseph]

hello I am looking to change my flat roof to a picthed roof for a prospective property. Its a 2/1 dupkex 1800 sq ft total. Is changing from pitched to flat substantually more expensive? Would anyone be willing to share estimates?

[Matt Devincenzo]

First option to do this is reframing and shingle etc. This route will require structural calc's and drawings, permit. This will be a very costly option, but could be good if you need it to implement central HVAC or another consideration. 

If you're just trying to eliminate ponding and/or insulate the roof better, then you should consider a pitched foam type roof system. For commercial roofing there are pre-sloped foam segments that will put a very slight pitch on the flat roof to allow better drainage as well as creating an insulated system. You probably still will need a permit for this option but it should be more of a re-roof type permit and not nearly as costly or involved to implement.