A legal claim filed against real property by a contractor or supplier who hasn't been paid, which encumbers the property title until the debt is resolved.
A mechanics lien (also called a construction lien, material lien, or supplier's lien) is a legal security interest that contractors, subcontractors, and material suppliers can file against a property when they haven't been paid for work or materials that improved that property. A filed lien attaches to the property's title, making it very difficult to sell or refinance until the lien is resolved.
The mechanics lien process is a powerful tool for construction businesses and tradespeople to protect against non-payment. Even if you're a subcontractor who never had a contract with the property owner, you can often file a lien against their property if the general contractor doesn't pay you. This gives you leverage to get paid that goes far beyond what a standard breach-of-contract claim provides.
Mechanics lien rules are highly state-specific. Deadlines to file are strict — often 60, 90, or 120 days from your last day of work — and missing a deadline can permanently forfeit your right to lien. Most states also require "preliminary notice" to the property owner before you can file a lien. If you're in the construction industry and doing significant jobs, understanding your state's mechanics lien procedures is essential to protecting your cash flow.