I thought in the US if you lived in a home for several years you could move out and start renting it out without refinancing for some reason. Do you have a resource for more info about this?
You can use a cash -out refi on your primary and use those proceeds for a rental (but you'll need lots of equity).
One can also get non-commercial loans to buy rentals but the terms (eg LTV, rate) are steeper than for primary.