Frame a new roof over an existing rafter roof

Its a story and a half so its basically a cathedral ceiling up stairs with a Pentagon shape and the slope is a 8 12. Its an older home. Can it be done ? Or will it add to much wait to the existing structure?

having a hard time visualizing what your saying but if your going to add a higher roof over an exiting frame then your fine if your going to be putting the weight directly over the joists buy adding a new structure that would be supported buy the roof trusses then no. not sure how you could get the weight directly over the frame with trusses in your way. roof trusses dont have a load rating that would support anything other then shingles and snow.

The concept I am getting at is first remove old roofing material then lay 2x4s on the flat over the sheathing where the rafters are… and there rafters not trusses… then sheet then put shingles on. Thanks for reading.