Where do ghost go when the building they haunt is demolished? I don't know. Some people say that spirits haunt the land, which means they don't go anywhere, they haunt the new building. Others believe only objects can be haunted, and that once you remove the haunted object from the property, the haunting ends. John Zaffis comes to mind. There's other theories and combinations of the two theories, but I could get sidetracked discussing irrelevant theories. After all, scientifically, you have to prove there even are ghost before you assert that anything might happen to them.
Point is, sometimes haunted places get demolished, and paranormal investigators are left with questions. Which is exactly what's happening to the Lotus Cafe and Cardroom, which is being leveled for make room for a high rise hotel:http://katu.com/news/local/after-92-years-sw-portlands-lotus-bar-to-close-for-high-rise-hotel-project
I saw the boarded up building for myself last week, and again this week:
I like to think that people would have tried harder to save a historic building, a haunted landmark, or at least a favorite hangout. But this is real life, the building is pretty worn down, business might not have been great, and a hotel really would be good for other businesses in the area.
So what will happen with the haunting? I've heard stories go both ways. Sometimes the property continues to be haunted when a new building is put up, such as the private home that was built on a site where a rectory had burned years before. Other times the haunting goes away, as was the case when another home owner tore down his porch to get rid of the residual haunting that keeping him up at night.
At the very least it'll be something interesting to keep an eye on if possible.