My wife and I are self-employed and each have our own home offices. We built a house this year and do not have a mortgage. What are our options for office deductions?

In previous years, we deducted a portion of our mortgage, taxes, utilities, etc, as a percentage of each home office. Can we charge our businesses appropriate rent for our home offices? Do we deducted/depreciate a portion of the total building cost for each home office?