Primary Residence -> Rental--> 1031 exchange

[Michael O'Driscoll]

Question regarding when is your property considered an "investment property." Say I have property #1 as my primary residence. I then decided to rent it out. I buy property #2. This is now my primary residence. How long does property #1 need to be rented out to be considered a investment property. Eventually I want to 1031 exchange property #1. Basically how long would property #1 need to be an investment property to be eligible for a 1031 exchange