During the time you're building a structure, it faces a different set of risks than it will after construction is complete. Between unforeseeable acts of nature—like floods and high winds—to human dangers like theft and faulty electrical wiring, there are myriad potential catastrophes from which you might want protection while you're in the construction phase. Contractor liability insurance can help make sure you're protected from dangers, from surprise fires to everyday slips and falls.
It can be purchased by the general contractor or the property owner, and is distinct from homeowner's or business insurance. While those might cover the building after people have already begun using it, construction insurance is specifically designed for the high-risk times while the structure is being built. Policies can also be written to cover the supplies used while building, so a faulty buzzsaw doesn't ruin your entire project.
In addition to making sound financial sense, construction insurance might also be a legal requirement for your building-in-progress. In some towns, you won't even be allowed to start building if you don't have some sort of coverage. It's important not just for the nuts and bolts of the construction, but also for the people fastening them: if there is an accident on your site, contractor liability insurance might be able to help with medial bills.
Even if it's not legally mandated, having coverage while contracting is a good idea. Mishaps occur, and even the sturdiest buildings can be at risk before they're finished. Getting general contractor's liability insurance can give you peace of mind while you finish your project.