We have just entered into contact on an investment property duplex.

Depending on your finances you don't necessarily need to start with a duplex, but I wouldn't go any more than 4 unit if you're going residential.

Now let's say one or both people making the purchase owned a condo previously where they roll over the proceeds/equity into the new purchase and put 40% down.

Thanks in advance,Rookie You’re going to struggle to find cash flow anywhere in the dmv, you would really be buying for appreciation only, both for ease and some upside, I’d look at some condos in dc, definitely some risk, but you can pick up a condo at a price you would have paid a decade ago. 

Building a 4,000-square-foot, three-story duplex with a 1,000-square-foot ADU could cost about $1.83 million, including construction and permits (excluding land).

BEAUTIFUL DUPLEX IN THE HEART OF MIAMI THIS PROPERTY IS SO UNIQUE IT HAS A AUD 1/1 ON THE SIDE THAT BRINGS IN AN EXTRA 1100 !

Just to confirm my understanding, you are living in a side by side duplex in Miami - you want to renovate the other side that you aren't living with a renovation loan?

Housing mix will change; more condos and co-ops and multi-family apartment buildings.

@Eli Jerman Owning a duplex where you live in one unit and rent out the other offers significant tax benefits but adds complexity.

I bought a single family because I thought I could house hack in the same way as a duplex and in ways it certainly could have and did work but I didn't expect the relational aspects of having people living in a property I purchased.