How would you value a private rooftop deck that comes with a top-floor condo unit (of a 3-4 unit property)? 

So we foreclosed on them (cost $1,000 in fees) then added a deck and a new metal roof ( $3,000) then started renting it for $500 a month to a new tenant, she rented it for 2 years and then we evicted her, put new carpet and laminate in ($3,000) then found a new renter for $500 a month for 1 more year.

This guy put in floors, installed cabinets, and built a couple of decks.

Other good inclusion: a security system, central air, new appliances, an "extra" room (dining room or den), a deck.

Here is a summary of what I have gleaned:Building Attributes: one level, ground floor, elevator in multistory buildings, no steps, universal design, wider doorways, smooth floor coverings without throw rugs, chair height toilets, hand rails, grab bars, bathroom near bedroom, laundry in unit or close by, good lighting, less square footage to take care of but enough to comfortably move around and to entertain visitors, close to bus stops, close to medical facilities, close to activities that interest seniors, garden, front porches, backyard patios/decks, quiet, warm, safe.Landlord Attributes: respectful, attentive, face-to-face communication, willing to adjust speaking speed and volume as needed, willing to do things for tenants to keep them off ladders and step stools (change light bulbs, hang pictures, etc.), willing to adjust policies and procedures to accommodate needs (alternative ways to pay rent, use of telephone instead of texting, etc), genuine interest in seniors' wisdom and legacy, willing to check in on the safety and well being of residents, willing to assume responsibility for yard work, snow removal, and keeping outside pathways clear of debris, willing to help tenants connect with community services as the need arises (cleaning help, food prep programs, senior services, etc.), service oriented.

Furthermore, the development has continued with numerous investors starting to purchase nearby. 8th Avenue, the main street, has Ennix Brewery, Dukes Upper Deck Cafe, there is an Escape Room, axe throwing, Voodoo Brewery.

Roofing replacement will run about $300/square though that doesn't include an allowance for decking replacement.On the electrical you'll probably need to either replace the panel or upgrade the breakers to arc-fault and then ground out the outlets. 

My goal is in two years, depending on the market, either "flip" the house, or keep it, rent both sides and purchase another house.The house has had some renovations, new siding, windows, roof, decks, etc.

The house had great bones but allowed me to learn by doing windows, siding, decks, painting, tile work, drywall, some electrical, driveway and just getting the confidence to take on projects.

I'm diggin' the upper covered deck.