Legal Question in Construction Law in Massachusetts

(1) Be competent to roof houses. While this is not a requirement, perhaps, in the sense you mean, if you are not competent to do it, and you do it and screw up, you can get sued;

(2) Have a valid construction supervisor's/home improvement contractor license on file with the state;

(3) Have the required insurance: injury, disability, worker's compensation, automobile...

...the following are not per se requirements, but if you ignore them, you do so at your peril. Moreover, you could lose out on a few tax advantages. Some of the entries below need to take place more or less concurrently, so permutation is less important than completion

(4) Obtain an employer ID number from the service;

(5) Choose an entity, and incorporate (term used generally);

(6) Be sure your insurance is in the name of the entity where applicable;

(7) Draft by laws/or operating agreement for business;

(8) Choose a name for your business;

(9) Draft a form contract spelling out the nature of your project (projects over $2000);

(10) Have an attorney on retainer in the event you are a subcontractor on a project;

(11) Find an accountant for a yearly audit;

(12) Don't mix up your personal money and your business' money.

...if you plan on hiring employees, there are a lot more things you would need to do, but that's a very dependent kind of answer.