Should I Buy Property and then Build a duplex on it?

[Bryan Laufenberg]

As everyone knows, the market is really tight right now and deals are harder to find. What I am finding are lots of properties for sale, many with more acreage that I could put on two duplexes or a fourplex. I have never heard much discussion about this approach, so any advice would be appreciated. 

Like:

How difficult is the process of getting loans? Will they qualify for a residential loan?

Do the numbers usually add up? (3 bed 1 bath typically rent for about $900 in my area)

Any other experiences people have had going down this road.

Thanks!