I have built an extension to my property and moved my mother into it as she is economically dependent on me. I’m prepared to spend signifacnt amounts of money to improve her property but want to make sure the property is at least in joint names before doing so. To me that means that I know I will definitely inherit so not lose the money invested but also that my mother has a fallback if she ever decides she wants to move back. If she ever decides to sell in the future once the property is in joint names what would her and my tax liability be if we sold it in the future? My concern would be if I had to pay capital gains tax (CGT) on half the value if it was based on her original purchase price. If my CGT was based on growth in the value from the date of the property going into joint names that would be less of a concern. 

Arthur Weller replies:
If your mother gifted half the property to you now, presumably there would be no CGT for her to pay because of principal private residence relief. Your base cost for any future sale would be today’s market value, as you will see here in HMRC’s Capital Gains manual: www.gov.uk/ hmrc-internal-manuals/capital-gains-manual/cg14530. However, if your mother moves out of the house today, any principal private residence relief for her in the future would be restricted