Mechanic's Lien
A legal claim placed against a property by a contractor, subcontractor, or supplier who hasn't been paid for work or materials, one that can cloud the property's title and, in some cases, force a sale to satisfy the debt.
Why it matters
It's one of the strongest tools a contractor has to actually get paid, since it attaches to the property itself rather than just being a claim against a company that might have no money left. For an owner, an unresolved lien can block a sale or a refinance until it's cleared.
On a real project
A drywall subcontractor doesn't get paid by a general contractor who's run into cash problems. Rather than just suing the GC, the subcontractor files a mechanic's lien directly against the owner's property, since the unpaid work is physically part of that building.
Who this matters most to
A Contracts Administrator tracks lien deadlines and requirements closely, since missing a filing window can mean losing the right to file one at all. A Project Manager wants to avoid liens entirely; one filed against the owner's property, even by a subcontractor the GC owes money to, damages the relationship with the owner.
Where this goes wrong
A general contractor pays a subcontractor in full, but the subcontractor never pays their own material supplier. The unpaid supplier files a mechanic's lien against the owner's property, even though the owner already paid the GC for that same work, and the owner is left fighting to clear a lien for money they've technically already paid once.