Draws from 203K loans can take time , contractors have wages and material bills to pay ."

On the other hand, the new proposal was to “remove the existing roof and apply XYZ material and waterproof, backed by ABC warranties” for $8000.

I buy a house using the BRRR strategy for $40,000, the cost of materials is 20,000 and it appraises for 100,000. 

Get some type of side job to cover the materials.

Concrete work is a common material expense.   

All of my education have been from BP forum members that offer alot of the same material at no cost you just have to find the Social media pages for their gems.

I would also replace the vanity if that was necessary and deduct the exact cost of materials and labor from the security deposit.Regardless of the number of homes, I wouldn’t be furnishing each home with vanities with mirrors inside them.

Once I close on house and contractor starts working on it, how do i deter people from breaking in and stealing materials?

It's not like the all-knowing MLS will open up to you immediately for free as soon as the state licenses you.The coursework and materials cost money and time.Additionally, realtor coursework often touches very little on real estate investing.

Get multiple bids and take middle one.Find someone local that can recommend someone or at least go to yelp or Angies list etc.Best way to add up costs is  to take the materials and a contractors day rate and go from there.