Beetlejuice Wiki

The Maitland residence was the home of Adam and Barbara Maitland, a recently married couple. Barbara and Adam cannot have a child together, therfore not have a family. Jane, the realtor who sold them the house wants them to move out for a family, for the house is too big for them. They both love the house, and plan to stay. 

After their death, Adam and Barbara are unable to leave their house by normal means; instead of stepping into the outside of the living world they encounter strange deserts and sandworms or end up in the Neitherworld Waiting Room.

While Adam and Barbara are in the Afterlife, the Deetz Family, who purchased the house from Jane, have made drastic changes to their home in under three months. Therefore causing the Maitlands to take action in trying to scare the family and eventually release Beetlejuice.

At the end of this movie, we can see that the Deetz Family and the Maitlands are coexisting in the house together.