@Clark Cannon If the margins are thin I'd consider having an extra cash cushion to weather any storms.

Slip Resistant Tiles: https://www.google.com/search?

The best we can ever do is to deal with that uncertainty and set our portfolios up to weather storms that may come our way.

I am super confused on weather the Banks use the gross or the net income to qualify for mortgage?

With NNN, the dynamics are a little different than other types of real estate, so it always depends on the use you are looking at, sales volume, technology resistance, and tenant quality.  

We did our best to communicate with the builder (I contacted customer care, site manager, new home consultant), but they don't provide emergency repair given the weather and it was Friday night.

I have never looked into it, but have spoken to people who have invested and done crops / commodities and its extremely dependent on weather conditions and one bad year can wipe you out for years to come.

After years of resisting taking in section 8 tenants I have one this year for the first time.

Should I use some heat resistant paint and spray the stack so it doesn't drip rust on the new metal roof?

Mainly saying it looked dangerous and unsafe from the wood being old and sheet metal warped due to weather.