I'm buying a 1970 single story brick ranch style home that is built above a crawlspace on a slope. Like many older homes, the interior consists of relatively small chopped up rooms and low ceilings. I love open concept vaulted timber frame designs, so I'm looking at future renovation options. The house is about 26' deep, so I'm sure timber frame trusses could be designed to span that size if I wanted to demo the stick built trusses and roof. What options are there for retrofitting an existing hours with a timber framed space? Could trusses be built on top of existing walls with some extra support at the foundation level or would we have to build an entire timber frame structure inside the existing walls? The whole house would be a structure roughly 26'x80' but a hybrid framing just the main living spaces would be 26' x 40'. Anyone have very rough numbers for what frames those sizes would cost including the roof and panels? Suggestions for how to tackle this?