Re: Should I replace the frame of my deck or build off of it?
re-using the existing may work it depends on two things, the condition of the existing framing and the configuration of hte new portion.
how do you plan on adding to the deck, make it longer or add a lower level or something? one thing to consider is the beam/ beams that are in place, they may need to be beefed up or old joists may have to converted to flush beams to do what you want.
your best bet is to post a photo of the existing and a sketch of what you plan to do
fire up the saw and make some dust