[header] How to add a spouse to a deed [title] Read your mortgage. [step] If you have a mortgage on your property, it may have a " due on sale " clause. This clause gives your lender the right to demand payment in full of the balance you owe on the mortgage if you sell or transfer some portion of your ownership. 
The reason: the property is the bank's security that if you don't pay your mortgage, the bank can seize your property. Obviously, if you sell or transfer some of your property, that gives the bank less security.