The real question is what kind of business is the roofing company. If it is a corporation or an LLC, then I agree with what JK posted.
However, if the company is a sole proprietorship doing business as a D/B/A then I would disagree.
If the latter, OP could work as an IC using his own name and running all transactions through the D/B/A. He would not need additional liability insurance if the nature of the work is the same as what his company does. But there are other issues such as workman's comp if working as an IC he has employees.