Its bad framing in roof construction, roofer should have pointed it out prior to his re surface. 

Roofing for 26 units, HVAC issues, resurfacing the shared parking area, etc. are all high dollar items. 

This property does need a new roof, fix roof leak damage, some interior fixes, new A/C units and eventually a resurfaced driveway.

Sunday evening, I check to see if the listing is still posted on Redfin, and it has resurfaced as a foreclosure, not for sale.  

We are building an addition, refacing the exterior with limestone, changing the roofline and installing a metal roof, replacing concrete, new landscape and resurfacing the parking lot. 

Set aside 10% of rent each month.Remember you always have to save money each month because sooner or later,you will spend it on new roofs,appliances,water heaters,minor storm damages,resurface driveways or parking lots,etc.Never stop saving,always collect it and set it aside.

I will add basic updates to keep property current but that was off your list (two tone paint, modern lighting, clean/current flooring, wallpaper removal, resurfacing counters, etc.).  

. $4000 per unit is budgeted in my underwriting for renovation.Building Qualities – 6 buildings - 33,200 SF● 1 bed 1 bath – 550 SF – 8 units● 2 bed 1 bath – 700 SF – 24 units● 3 bed 1 bath – 750 SF – 16 units● Two-story● Individually metered electric, landlord paid water● Central heating and air● Copper Pipes● Built: 1975 ● Pitched roofs – All replaced in August 2007● Onsite laundry facility – Units purchased 2012● Parking lot resurfaced 2005● All units in good shape, with minimal cap ex required● 1 mile from 5 star public middle and high school● 4 units recently renovated with $100 rent increasesThis is definitely a tertiary market, but population growth is on a slow rise (1% from 2010-2016).

Is it more cost-effective to resurface the original hardwood or just get new flooring throughout?

As for the interior, I would resurface the kitchen counters (<$1000) and many of the companies will do the same for the cabinets and just change the hardware as long as they are structurally sound.