CT isn't cheap so if you plan on doing it there you are going to surprised at how poorly you do. maybe in the suburbs I'm not sure but as much as I know people call us from CT and everyone is rich and has lots of money and things are expensive out there. build to rent is a great model. we build 3 story walk up infill and keep it to the residential side. 3 units is the most units before it's commercial and you need engineering, etc. check comparable and things liek that. we came up with this design a year ago and we sold 10 if you want to talk further please DM me happy to connect. there are some great build to rent conferences. we went vertical not horizontal with it to save on build costs and design to fit on any infill lot. this fits on a 3500 square foot lot. most lots in our area are 30x120 or 30x150. in miami where I live now they are 50x100 or so. but any infill lot we can pretty much get this one on. there are some great build to rent conferences coming up too that if you like this topic I'd recommend attending I'm sure you'd learn a lot.  

Quote from @Nicolas Tow: I recently purchased a 3,125 square foot empty lot in the 27th ward area of Humboldt Park Chicago and I was wondering how difficult it is to re zone from RS-3 to RS3.5 or RT 4.

I've seen estimates of $200 to $400 per square foot for SoCal with $700 sq ft for something higher end and building up a hill and but possibly higher for San Francisco Bay Area (lhigher labor costs, etc.).  

I was lucky enough to have purchased before a surge in the London housing market, so I got my foot in the door for 280k CAD.

Purchase price: $171,000 Cash invested: $29,000 Small 600 square foot cabin tucked away just outside of the quaint city of Ellijay GA.

However if you have enough reserves, 6mo or greater then I'd say chance it but a couple of missed payments from the tenants and you have to foot the payments out of your own pocket.I'm all for taking risks but I think you really need to evaluate the age of the major systems so you don't get hit with a bunch of cap ex all at once as well as your reserves. 

Reason I ask is because full gut estimates I’ve gotten have been around $150 per sq foot.

I was very relieved when I saw how much I avoided paying just for those two things.

I'd be looking at multiple structures. we try to build below the average new build cost in our market in Columbus Ohio which is 515,000 last year and we target land 40-50k and urban core adjacent where we get higher price per square foot. we build for clients with margin around $190 a sq ft depending on multi or single. we can get that down in our triplex it's a little higher on our single family homes because of garages and limited economies of scale. hope that helps. idk Philly but if you show me the area and styles of homes I can give you some more insights. 

I got my $50k, and I'm relieved from my $150k loan.