We gave him a deposit for the purchase of the materials ($1500) and he disappeared.

Welcome @Jordan Carty There is a lot of good material here.

If you're the seller you would want to provide disclosures of any significant issues concerning your property to a potential buyer when they're looking at the property, if you're listing with a real estate agent/broker then you should provide instructions in the listing agreement to make such disclosure in their written or online materials for the property.Making a disclosure of existing issues, or known potential issues that you know as fact could potentially negatively affect the property will reduce the burden of surprise during negotiations and mitigate the risks of potential future lawsuits. 

Tuition, books, materials, etc. 

If you really are interested you can get a consultation from a real estate attorney for a relatively small fee.I do not know the disclosure laws in your area, but where I live, if the property owner has taken reasonable steps to fix the material defense and reasonably believes the problem has been address, then it does not have to be disclosed.

Flat roofs are expensive to get replaced and do work on.On a 10,000 sq ft pharmacy building cost to replace is about 20k to 25k all in.Some of the older membrane materials dry up and crack causing leaks.

I'll spare the details but the first crew whom I've worked with before and are proven, charged me $6,500 WITHOUT materials.  

@Troy Fisher I have seen your name many times as I have combed through Seattle related materials here on BP.

Between all these locations, we have found about another $1,000 to $1,500 in antiques and building materials that would be good in lower end rentals.Basically, with a little legwork, we should have no problem recouping about 8% to 10% of the purchase price of the home just by reselling the items contained within.Does anyone else regularly deploy this idea?

I'll plan to post every week or so with a progress report and any new material information.