Do it yourself

I recently had a house fire that caused mostly smoke damage. My adjuster came and determined that the entire inside of the house needs to be painted and my floor in the kitchen needs to be replaced. The amount is 10k plus. I am a builder myself and would like to do the repairs myself. They will only give me the full amount if i use a contractor. Can i use a contractor, who is a friend, but still pay others under the table to get the work done?
I want to do more repairs and improvements than what actrully needs to get done. Is just getting the money written to myself the best way to go?