CA Civ Proc Code Section 704.820

If the dwelling is owned by the judgment debtor as a joint tenant or tenant in common or if the interest of the judgment debtor in the dwelling is a leasehold or other interest less than a fee interest:

(a)

At an execution sale of a dwelling, the interest of the judgment debtor in the dwelling and not the dwelling shall be sold. If there is more than one judgment debtor of the judgment creditor, the interests of the judgment debtors in the dwelling shall be sold together and each of the judgment debtors entitled to a homestead exemption is entitled to apply his or her exemption to his or her own interest.

(b)

For the purposes of this section, all references in this article to the “dwelling” or “homestead” are deemed to be references to the interest of the judgment debtor in the dwelling or homestead.