The property has 2 unites, around 1,600 sq ft and is going for $65k Apparently the roof is less then 7 years old but upon inspection it was discovered the roof has fire damage.

A new roof or ac unit may not be too obvious if snow covered when the appraiser comes out. 

Yes, a Buyer may want to confirm things by paying their own inspector, but if you can get an accurate picture of the roof, HVAC, plumbing, sewer, and electric, that eliminates 80% of the mechanical problems that cause Buyers to back out.

remodeled the units and roof What was the outcome?

I was in way over my head and as a result I racked up a bunch of 30 day mortgage late payments. 

Luckily, most of the work that needed to be done was cosmetic, but we budgeted for a new roof, new HVAC unit, exterior landscaping, along with interior cosmetics.

It has a new roof; paneling needs to be removed; new doors; updated bathrooms; some landscaping; outside paint job.

It was a hard sell convincing them to spend the money especially when I presented them the roof quote, but the demand for housing is great in the Medical District. 

Capex is half of what I use. 10%.My capex includes roof 25 year life span, floors 10 year life span, appliances and hot water heater 12 year life span,hvac 20 year life span, bath and kitchen remodel 20 year life span.

I have a detached garage which is more than three feet from the main structure, however the roofs of the two structures are touching.