(770 ILCS 60/1) (from Ch. 82, par. 1)
    Sec. 1. Contractor defined; amount of lien; waiver of lien; attachment of lien; agreement to waive; when not enforceable.
    (a) Any person who shall by any contract or contracts, express or implied, or partly expressed or implied, with the owner of a lot or tract of land, or with one whom the owner has authorized or knowingly permitted to contract, to improve the lot or tract of land or for the purpose of improving the tract of land, or to manage a structure under construction thereon, is known under this Act as a contractor and has a lien upon the whole of such lot or tract of land and upon adjoining or adjacent lots or tracts of land of such owner constituting the same premises and occupied or used in connection with such lot or tract of land as a place of residence or business; and in case the contract relates to 2 or more buildings, on 2 or more lots or tracts of land, upon all such lots and tracts of land and improvements thereon for the amount due to him or her for the material, fixtures, apparatus, machinery, services or labor, and interest at the rate of 10% per annum from the date the same is due. This lien extends to an estate in fee, for life, for years, or any other estate or any right of redemption or other interest that the owner may have in the lot or tract of land at the time of making such contract or may subsequently acquire and this lien attaches as of the date of the contract.
    (b) As used in subsection (a) of this Section, "improve" means to furnish labor, services, material, fixtures, apparatus or machinery, forms or form work in the process of construction where cement, concrete or like material is used for the purpose of or in the building, altering, repairing or ornamenting any house or other building, walk or sidewalk, whether the walk or sidewalk is on the land or bordering thereon, driveway, fence or improvement or appurtenances to the lot or tract of land or connected therewith, and upon, over or under a sidewalk, street or alley adjoining; or fill, sod or excavate such lot or tract of land, or do landscape work thereon or therefor; or raise or lower any house thereon or remove any house thereto, or remove any house or other structure therefrom, or perform any services or incur any expense as an architect, structural engineer, professional engineer, land surveyor, registered interior designer, or property manager in, for, or on a lot or tract of land for any such purpose; or drill any water well thereon; or furnish or perform labor or services as superintendent, time keeper, mechanic, laborer or otherwise, in the building, altering, repairing or ornamenting of the same; or furnish material, fixtures, apparatus, machinery, labor or services, forms or form work used in the process of construction where concrete, cement or like material is used, or drill any water well on the order of his agent, architect, structural engineer, registered interior designer, or superintendent having charge of the improvements, building, altering, repairing, or ornamenting the same.
    (c) The taking of additional security by the contractor or sub-contractor is not a waiver of any right of lien which he may have by virtue of this Act, unless made a waiver by express agreement of the parties and the waiver is not prohibited by this Act.
    (d) An agreement to waive any right to enforce or claim any lien under this Act, or an agreement to subordinate the lien, where the agreement is in anticipation of and in consideration for the awarding of a contract or subcontract, either express or implied, to perform work or supply materials for an improvement upon real property is against public policy and unenforceable. This Section does not prohibit release of lien under subsection (b) of Section 35 of this Act, nor does it prohibit an agreement to subordinate a mechanics lien to a mortgage lien that secures a construction loan if that agreement is made after more than 50% of the loan has been disbursed to fund improvements to the property.
(Source: P.A. 100-920, eff. 8-17-18.)