Different contributor here.. The question hasn't been transferred to business law, but I'm qualified in Family, Business, and practically every other type of legal category. Please permit me to assist.
First, as you're probably already aware, except for municipalities, the state has few regulations concerning contractor licenses (cf, Home Improvement Consumer Protection Act, Crane Operator License, Asbestos Removal License). So, the issue effectively devolves into what the municipality actually requires.
Since your municipality only licenses persons, you cannot hide behind your business entity, regardless of how you try to structure your business. Any liability that would attach to you, while that would not permit a creditor to directly reach your business assets, the creditor could get a "charging order" against the LLC to pay over any profits to the creditor. Then, you would have to decide whether or not to distribute profits.
Pennsylvania law does not permit wage garnishment, so if you were sued and a judgment obtained, you could take your profits as wages and avoid garnishment. So, there are ways to get around a judgment creditor. But, a personal judgment certainly would create problems for you, so the only real solution to your issue of liability is to purchase professional liability insurance that will protect you personally from the cost of legal action -- since you cannot escape liability if your work goes awry.
Concerning the corporate veil itself, Pennsylvania has a "strong presumption against piercing the corporate veil
." And, the general rule is that "the corporate veil is properly pierced whenever one in control of a corporation
uses that control or corporate assets to further one's own personal interests." College Watercolor Group,
468 Pa. 103, 117
Given your personal interest in a license, and the intent to use that license to repair and improve your business' profits, I can see how it would be quite straight forward to claim that you and your business are "one," for the purposes of any work done by you on your own properties. The legal rationale is called "respondeat superior," and it holds that a business organization is liable for the acts and omissions of its agents done within the scope of agency. And, since you are an agent of your LLC, your LLC would be liable for practically anything you do.
The point is that the corporate veil theory doesn't apply to your purposed activities. "respondeat superior" applies, and your LLC would be easily attacked by a creditor based on this legal theory.
Hope this helps.