Empty buildings are typically priced using a price per square foot. 

You also need to include property taxes and insurance in holding costs.For rehab, I would estimate it based on what the property actually might need based on those photos, not a dollar per square foot number.

ive bought 3 rental properties with my VA home loan in WA (duplex, quad, and a triplex).

I am trying to figure out how much it might cost to convert a detached garage into an ADU in the greater Portland, OR/Vancouver, WA metro area.

Washington, D.C.· Top 3 Employment Industries:o Education & Healthcare: 15.1%o Government: 28.0% o Financial: 3.5%· Average 1 BR Rent: $2,234· Renter Occupied Housing: 56%Sources:www.ngkf.com/insights/market-report/united-states-multifamily-capitalRentCafe.com

I am also considering purchasing my first property in the Valley as prices are more affordable per square foot.

Incredible value add opportunities for square footage and automation.Coffee in the local cafe at breakfast time is a wonderful purge of the soul. 

Then lookup the zoning ordinance to find our how many units you can have per a square foot of land.For example, your town might be 1 dwelling unit per 1,500 square feet of property.

Here in Wa we get first, last and security deposit, the more you get the better you tenant will behave.

Have you research about Washington?