Do you save three months of vacancy for each unit and $50,000 for the roof replacement?

We built a single family home version of a 2 bed 1 bath with surface parking at cost with no profit all in with land for 175k in newark ohio, a suburb of columbus ohio. when we push that to 3 units and closer to the city for our build to rent model the numbers go way better. a 30k slab for a single family home is 30k, a 30k slab for a triplex is 10k a door. we designed a 2 bed 1 bath design at 668 sq ft and it's very good layout even I would live there, but I would never build anything that small again. there's no economies of scale. you need density and shared lines, resources, shared roof shared slab, shared windows, etc the cost goes way down.

My duplex - built 1989, 2,060 sf, 2 bed/bath, 1 year old roof, value if I subdivide (county already approved) and sell each separately $150k each ($300k total)Investor duplex - built 1995, 2,300 sf, 2 bed/bath, 5 year old roof, value around $310kThe investors initial request was for an equal trade and they would pay realtor fees, which I replied wouldn't be equal due to buying/selling costs (recording fees, title insurance, closing fee, survey, inspections, loan fees, 1031 fees, accountant fees, repairs), taxes would increase due to new sale price, I'd trade a 3.75% mortgage for a higher one, and I'm on the 10th year of a 30 year loan so resetting that to a new loan would restart amortization and pay more towards interest.

A good condo board should be saving money for larger projects as they are known in advance (eg every 25 years you need a new roof). 

Like you said, I do believe you'll see more firms with "all services under one roof" moving forward. 

some roofs, tree damage and trash strewn around. 

So 50% of the roof depreciation would be depreciable.

The house was vacant for 5 years with a new roof (5 years ago). 

A couple of Roof claims due to storm damage in Tucson, and we had several sub-to deals in Oklahoma when grapefruit size hail decimated a big section of the whole town. 

Roof lines, window styles, and masonry/siding all play into this natural flow, and the biggest mistake you can make when designing your flips is not following the flow that is already present!