I pay an accountant a lot of money to figure that stuff out. I'm not really worried about it though. I don't think buying a rental house with a ROTH and plowing all the income back into said ROTH is an issue in either of those cases. As far as trying to write off a new truck or something equally as stupid in the process... well... duuuuh. The disasters I think one could find oneself in would be the result of putting the gun to one's own foot and pulling the trigger. On cursory looks... and I have not done the deep dive on it but as long as everything stays within the SDIRA, I don't see taxation as an issue with the possible exception of being without a renter and having to 'loan' the IRA some money to cover any mortgage that you might have.