How do I work out the value of my share in a joint-owned house?

Q I bought a flat with a good friend more than three years ago. I paid the deposit in cash and we share the rest of the equity in the property equally, so I have a 55% share in the property. In May next year I am getting married, and my fiancée already owns her flat where I will be permanently resident. I have therefore been looking for ways to sell my share. My friend wants to remain in the house but is unable to buy me out. However, his father has suggested that he buys me out. I have been given conflicting advice by my family and my friend. He has said the deal should be really simple as his father just buys my share for what I have so far invested. Conversely, my family has vigorously recommended getting at least three local estate agents to value the property independently so we have a current value with which to work. I really do not want to strain the friendship, but also want to make sure we are working towards the best possible way. What should I be aware of and what should I be doing? LC A You should definitely be listening to what your family have to say. If you were to sell the flat on the open market you wouldn't work out the price based on what you have invested so far; you would sell it at a price based on its market value. So get three estate agents round and work out an average of their valuations. What your friend's father should pay is 55% of the average.