You have a lot to worry about overseeing a construction project. The last thing you need is to end up with a mechanic's lien on your property. A mechanic's lien is a claim against your property for an unpaid invoice to a contractor, material supplier, subcontractor, or laborer. A lien can happen if your general contractor fails to pay one of the other providers. Here are five tips to help you prevent a mechanic's lien.