If you formalized that model via church youth groups or the local Food Bank (extend it to include a Job Bank) you'd have the local illegal problem solved overnight.
Can't be done.
Rules, regulations, laws, and permits put a stop to all formalizing it. If you want anything done to your house and not involve a contractor, you have to break some law or another.
It's worth checking around. In my town, a couple of charities and rescue missions have "day labor" programs to help those who have been down and out get back on their feet. Your work gets done, and you have the benefit of knowing you have helped others.