There's also physical damage, wear, short-lifetime assets like asphalt paving, bulbs, paint, etc.

In my opinion, nothing beats "pounding the pavement".

The 'Frame' will drop the comp slightly compared to brick, and the 'Slate' will raise the comp (an unknown amount, as per my experience) compared to asphalt shingles.I don't want to nose in on your lead, but you should also look at the 'time on market' and 'time to sell' all around the property to get an idea what you are up against.Cashflowing $1k, or making $1k in rent per month?

What is the price difference between just different types of roads (Asphalt, Concrete and Gravel)?

My best advice to building a successful Commercial book of business is to pound the pavement the old fashion way. 

I advertise very minimally now, and that is because I pounded the pavement years ago, built a network by forging relationships.

Did everything burn including block foundation, concrete slab or asphalt driveway ?

I looked at the condition of the sidewalks and street asphalt, checked out how many people were walking their dogs or generally around after work and on weekends. 

My baby girl is now 17 months and I'm jumping back into the game with both feet and excited to hit the pavement.

Investors will always need reliable, smart agents to pound the pavement.