Yes, it would be useful.
Here are the steps involved:
a) check if the city allows it, as your side of the street may not allow 2 titles per lot. i.e. inquire about zoning at the city planning department. a phone call.
b) check if the mortgage can be ported to two properties, as the bank has to approve this sub-division, and they may not. If they allow it they bill you legal fees perhaps .. $1000-$3000.
As such, you will likely need an appraisal. Say another $1000.
c) you need a new survey - say $1500 to $2500 - with compliance stamp from city.
d) compliance may be free, or may cost $50,000 depending on state of affairs of utilities (water, sewer, gas, electricity - do you have two meters each ?), porches, overhangs, windows, roof slopes, setbacks, current regulations, furnaces, parking lots, garages i.e. what worked for your neighbor a block away may or may not work for you.
e) you need to submit it to land titles. Survey firm can do that for you, or a lawyer. say another $800 to $1500.
To sell one half, you need to discharge the current mortgage and get a new one for the remaining half.
So, all in maybe $5000 if no physical work is required on property, and easily doable in 3-5 months, and quite profitable as 2 legal half-duplexes might be $100,000 more than one full duplex.
Item d) is where you will find most surprises and potential costs.
oh yes, there is one item I forgot if successful:
f) party in Hawaii - $10,000 !
