Would this Renovation make sense

[Ryan Cleary]

Have had this duplex for less then one year. Paid 220k with a current cash flow of around 10%. The surrounding properties are all 4-units (most of them are two separate du-plex on the same property if you notice the picture).  We have enough land to add another 2 units and parking spaces.  The land is zoned appropriately.  We would be using hard money or a construction loan and try to refi after 6 months.  

I just spoke with an architect and found out the construction costs are going to be around $250 per sqft.  So these would be the numbers.

325k for construction

13k permits and misc

20k for architect (guessing on that  number)

So lets call it $360,000 in total to build the two extra units.

Monthly rents for those two units would be around $1,400 each ($2,800 in total)

Is this even worth looking into?  Thanks!