I have discussed why contractors need to incorporate previously here at Construction Law Musings. Among the many reasons to incorporate are possible tax benefits and the protection of personal assets (like your house and your dog) from judgement and collection actions. This latter reason is key in the construction world in which Murphy can look like an optimist and projects have so many moving parts that something is likely to go wrong.
The reason incorporation works as at least a partial shield is that the company and the owners are separate “people” or entities from a legal perspective and a contract with one “person” cannot be enforced against another. This same logic applies in the context of corporate versus individual actions, i. e. the actions of one person cannot be legally attributed to another person. By extension the assets of an individual cannot be collected to satisfy a purely corporate debt or judgment.