There are a lot of seniors who are stuck having to rent privately and can never afford to buy their own home.

Some people buy a home together to be able to afford their own piece of property.

This is done under tenancy in common. Married and defacto couples will usually own their home as joint tenants. They each own all the property and none of it. That is they have no right to leave a half share in a will as it is impossible to own a slice, you both own the property jointly. When one joint tenant dies, the surviving partner now owns the whole property and can dispose of it as he or she wishes.

Tenants in common buy property together but actually own their slice of it, which can be sold or left in a will as heirs. This is a good mechanism for people who are not couples to buy property together.

For example, two or more people buy property together. This makes the property market much more affordable to those who could other wise not afford it.

For example, an 8 bedroom, 3 bathroom home was for sale recent in Maryborough Qld. 8 people buying together would be up for around $37, 000 each. They would still be entitled to any relevant state or federal grants. If council approved for dual occupancy, they could sell of the back yard and divide the profits. Or build a granny flat to rent out to add value. If qualifying for a mortgage, could apply for one.

Of course, this scenario could go wrong, but a legal agreement is available to be drawn up to cover all eventualities. 

People could have their own locks on their own doors. The rest of the house would be common areas.

People do do it, and it seems a great way to get into property, instead of being in private rental.