Of course, these are old buildings and there's 9 steps that no "estimating guide" includes, like sanding and putting poly on the floor under the cabinet you tear out to keep the cat urine odor in, etc.

In regard to approval or disapproval of a potential tenant this Is being a little to intrusive asking for a urine test from a potential tenant.

TONS of great info Thank you so much for doing those Brandon Turner.One hurtle I'm having problems understanding is dealing with private money lenders and flipping.

While in the house I noticed there are a few piles of feces and urine in the basement (which is completely unfinished, bare concrete floor and walls). 

There are over 50 cats living in the home so the place reeks of urine. 

Some say chlorine solution but I’ve read that urine can create gas with amonia.    

No urine or pet smells. 

Had a friend stop by to see the progress, and he smells cat urine, without any knowledge of what I ran into initially. *@!

Any advice on how to over come this hurtle?

Slaying or neutering shows that the owners are responsible and it decreases the chances of the pet marking their territory with urine.