[svandamme]

eeh, how can you give 20 K to a contractor up front, unless it came with a clear contract that tells him what he has to deliver for that 20 K?

sorry , but i'm confused about that

for something as simple as a concrete slab ,
i would want a fixed price , pay 1/3rd up front, 1/3rd when they start, 1/3rd upon completion
any screwups or cost over-run, he can eat it