How to Convert a Flat Roof into a Pitched Roof
The typical way is to remove the existing roof and add new framing to the home that creates a pitched roof over the old flat roof area. On houses, new pitched roofs typically are supported by the exterior walls, as with standard sloped-roof construction. Likewise, the structure can be built with engineered wood trusses or traditional rafter framing. If a conversion is not possible, adding tapered insulation to the flat roof will give the flat roof enough pitch to drain effectively without the expense of new framing.