I'm buying a property with my sister – what happens if I move out?

Q My sister and I are first-time buyers and like many others we want to take advantage of the stamp duty holiday. Neither my sister or I can afford to buy on our own. I’m currently in a long-term relationship and when my partner and I get married it is likely that I will move into his house. This will probably happen in the next few years. I don’t intend to have any ownership on his property so my contribution would be towards bills.

A property with my sister would be an investment for myself particularly if things do not work out with my partner. This property would be for us to live in with a 50/50 split. However, if/when I move out, should I still pay the mortgage? It didn’t make sense for me to pay a mortgage for a property that I’m not living in. Having said that I won’t be paying towards the mortgage at my partner’s place. Any advice would be greatly appreciated.
HR

A Yes, you should still pay the mortgage if you move out. As you and your sister will jointly own the prospective property so you should be jointly responsible for the mortgage whether you are living there or not. It would be reasonable to stop paying your half of the mortgage only if you stopped owning your half share of the property. You should also continue to pay half of the buildings insurance premiums as well as half the cost of any improvements to the property – such as an extension – which increase the property’s value.

However, it would be perfectly reasonable to stop paying half of the costs associated with living in the property such as contents insurance, council tax and the gas, electricity and water bills. If your sister doesn’t plan to take in a lodger to help out with bills, she might like to know that if she plans to live alone after you have moved out, her council tax should go down.