Renovating a duplex and renting i?

[Michael Karl]

So my dad was very interested in getting into rental properties so I offered to help him out with his first deal. He purchased a bank foreclosure duplex that was not in liveable condition.  Since he made the purchase we have completely gutted both sides and are in the process of putting them back together.  One of the sides was not as bad as the other so the less intensive side is moving along quicker then the other.  The question I have is it a bad idea to finish one side and rent it out while we are still doing major work on the other unit?  Has anyone done this and run into problems? lower rent because of construction? Tennant complaining about work being done? 

My hope is to stop trying to work on both at the same time, get one finished and rented ASAP and then focus on the other to have it rented before the end of the summer. 

Any input or ideas would be greatly appreciate  thanks