People who do not have tenants in the building that they are buying will have to show that they can afford to make the monthly payments based on their own income. That's why the best thing to do is look for property that already has someone renting it. No lender will accept 100 percent of rental income as projected income because there are expenses to being a landlord. If the place has to be painted, requires foundation work, or needs a new roof, it's the property owner who pays for the improvements. Even though landlords can write those costs off on their income taxes, they have to have an income to write them off against.
Expenses can easily climb higher than income.
Let's make one thing clear. Any building with more than four units is considered commercial real estate and it is governed by a different set of rules. Some people think owning rental property is going to be a cake walk. Then they realize they have to maintain the place. That can be expensive.