The building's bones are from the early 1900's, but if there was a leak, there would be some residue on the floors, ceilings and/or walls... 

For some years now I've been fascinated with the idea of building wealth through real estate.End Goal: In a nutshell, I want to build long term wealth via residual income for me and my family.With the information I've accumulated, I've decided I want to go the investor route.

This is important no matter what you're going to paint it with as you need to remove the tar residue so the paint can adhere.The we painted it with the oil based Kilz (not the latex Kilz 2) Then we painted it with our usual top coat paints.Every piece of flooring was replaced.

Some residual cash (prefer not to use any more of my own money or at least minimal), trying to scale up .

I'm about a month or so out from 48, so getting to "my number" in residual cashflow is obviously important to me, but I'm also fascinated by the potential repositioning has on building net wealth.

Likely its just the adhesive they used back in the day. 

Your rent income minus all the monthly expenses (mortgage, property tax, insurance, property manager, repairs, vacancy, etc.) leaves you with $150 of residual income.

@Adam ByrneBased on what you're saying it sounds like your investors would like some sort of residual income. 

You can spray them but you're supposed to backroll the walls to get proper texture and adhesion. 

(6)how do you make lots of residual income?