I'm trying to understand what you can put as a contingency since there no roof or foundation to blame and get out of the contract.

I always check the foundation, roof, hvac, sewer (septic), windows.

My own roof has lathe installed because it is my preference.

Roof 15 years old. 

Tenants do not have the financial wearwithall to handle roofs, ACs, furnases etc etc.   

For example, I bought a duplex this year that had brand new furnaces, hot water heaters, and AC units, and a roof that is 4 years old.

But it will need a LOT of work, insulation, updated wiring, new roof, heating system, and potentially a foundation.

It's got a flat roof that I haven't seen replaced in the past decade. 

Can you imagine going into a gas station with a sign out front saying gas was $2.59 a gallon, and when you went to pump the gas you first had to pay a $15.00 fee for using their pump, an $8.00 "lot fee" for parking you car in front of their pumps on their property, a $17.00 "roof" fee because there is an awning over the pumps, and a  $14.00 "snack bar" fee to cover the fact that should you feel the need for a cool refreshing beverage, you have the option of walking in and purchasing an Icee for $1.99?

We got the inspection back today; the issues are as follows: mold beyond the surface mold we originally noticed when checking the house out, wood rot in left side floor, damaged roof joist, poor ventilation in the attic and mold, many of the chimney bricks are loose, standing water in crawlspace--potential mold, leaking shower and toilet leading to damaged floor/ceiling underneath, plumbing material issues, electrical not all properly grounded.