"Joint mortgages are commonly associated with couples buying together. But you can also use them to purchase a house with friends or family members, with some lenders allowing up to 4 people on a mortgage. This might be an option to help you and others on to the property ladder, but make sure you consider all the implications before taking on a mortgage with others."
You can borrow more than if you were taking out a mortgage by yourself
It may be easier to save a larger deposit as multiple people are contributing
If you are unable to make the mortgage payment for any reason (sickness for example), your partner or someone else on the mortgage may be able to cover your share for a time