What is a Mechanics' lien?

A mechanic’s lien is a security interest that is used to ensure payment. Any person who works to confer a benefit upon real property (sometimes personal property, too) may assert it under Missouri law against the real estate he or she is improving. Think of it as simply collateral. If the property owner cannot or does not pay the mechanic improving the property, the mechanic in turn will have a lien which will run with the property (ever wonder why title checks on real property have to be run before buying a house?).
The lien must be asserted within six months. Original contractors are not required to give notice, but all other parties are required to provide the property owner with 10 days written notice prior to the filing of a lien claim. The alleged lien must then be filed in the with the appropriate recorder of deeds within 6 months of the indebtedness. This notice must contain a legal description of the property, the name of the owner and contractor, and an accounting of the amount due pursuant to the lien.
Even though mechanic’s liens are broad in Missouri (e.g., they are even assignable) they cannot be asserted on any type of property in Missouri and in all circumstances —
There shall be no lien involving the rental of machinery or equipment unless:
(1) The improvements are made on commercial property;
(2) The amount of the claim exceeds five thousand dollars; and
(3) The party claiming the lien provides written notice within five business days of the commencement of the use of the rental machinery or equipment to the property owner that rental machinery or equipment is being used upon their property. Such notice shall identify the name of the entity that rented the machinery or equipment, the machinery or equipment being rented, and the rental rate.
RSMo 428.010.
If you have a question, problem, or concern about effectuating or addressing a mechanic’s lien, seek appropriate legal advice.