I think you could also check their credit history and see if this issue is compounding elsewhere in their finances.How do they pay currently?

You say to yourself, "If I can anticipate getting $300,000 sales price for this property at the end of 5 years, what amount of money would I need today that if I invested it at x% interest compounded monthly, would grow to $300,000 by the end of five years?" 

Would prefer not to, however, looks like i'm in need of a new roof (previous owner piled on layers of roofing and now causing some bowing of structures holding it up.  

I have read that a product called Green Glue Noiseproofing compound between regular sheetrock layers can work as well.  

If compounded fast and high enough, my goal is to be able to take cash out yearly and never reduce the account balance. https://www.biggerpockets.com/forums/49/topics/465957-why-you-should-become-a-hard-money-lender

Leveling compound and glue have an odor.

What's more, the bids you receive from the contractors/vendors for specific components of the reno will differ, as well as the co-op's policies towards renovating, further compounding this variance. 

., so if it's a 2 year loan, for each $100k you borrow at (say) 12% interest-only, you pay $12k in the first year (plus any fiddly compounding or other fee that would indicate that 12% was a lie), then the SAME $12k(+) amount is paid again during the following year.

All the money the landlord thinks he is saving every year by not fixing things or having his handy tenant fix them compounds annually and the repair bill becomes so high they end up selling the property for pennies on the dollar to investors. 5.

@Bill Leonard  HORRIBLE deal  @Charlie Fitzgerald   return FAR to low..Gap funder should get 50% of upside minimum... not a measly 12% apr on accrued basisyou guys really need to take a step back.you should go see a local HML... check out Norris group in LA they take investor funds.Not sure if Charlie takes on investors on a one to one basis or through a PPM.. but someone with his experience is the bow you need to shoot your arrows.Again this is a HORRIBLE Risk/Reward scenario and the person advocating it has just hit the lottery if he or she can suck investors into that scenario.