Changing ownership of house to children

As I'm getting older I'm wondering if it's possible to change the ownership of my house to my stepson without me having to sell it to him as I know he will have a lot of inheritance tax to pay if we wait till after I die. ( I have no natural children or siblings)

What fees and taxes would we have to pay if I make a gift of it to him? It's only half restored, so not terribly valuable, but what valuation would be put on it?