Construction Lien: A construction lien is a legal claim on property or assets owned by an individual or organization, designed to compensate those who have provided materials or services (such as labor, supplies, or subcontractors) for building or improving premises. A construction lien is effective until the debt and related costs are fully paid – protecting contractors and other suppliers from nonpayment. With construction liens in place, real estate investors can ensure they can do their jobs while also protecting themselves from potential losses.