Md. Code, Real Prop. § 9-103

(a) A lien established in accordance with this subtitle shall extend to the land covered by the building and to as much other land, immediately adjacent and belonging in like manner to the owner of the building, as may be necessary for the ordinary and useful purposes of the building. The quantity and boundaries of the land may be designated as provided in this section. (b) An owner of any land who desires to erect any building or to contract with any person for its erection may define, in writing, the boundaries of the land appurtenant to the building before the commencement of construction, and then file the boundaries for record with the clerk of the circuit court for the county. The designation of boundaries shall be binding on all persons. If the boundaries are not designated before the commencement of a building, the owner of the land or any person having a lien or encumbrance on the land by mortgage, judgment, or otherwise entitled to establish a lien in accordance with this subtitle may apply, by written petition, to the circuit court for the county to designate the boundaries. (c) (1) If a building is commenced and not finished, a lien established in accordance with this subtitle shall attach to the extent of the work done or material furnished. (2) If a building is erected or repaired, rebuilt, or improved to the extent of 25 percent of its value, by a tenant for life or years or by a person employed by the tenant, any lien established in accordance with this subtitle applies only to the extent of the tenant’s interest.