Here is a great case study on shareable.net about sharing a house written by Janelle Orsi, attorney. The people are based in California, but the advice applies anywhere.
I’ve written before about sharing houses, in Suffolk and in Streatham.
To make this work you do need to put in considerable thought, discussion and negotiation at the beginning, but the benefits can be very significant. As usual with sharing, the economic benefits are usually the reason people first consider sharing: the community and social benefits become the ones they get the most pleasure from over time.