Va. Code § 43-2
For the purpose of this chapter, a well, excavation, sidewalk, driveway, pavement, parking lot, retaining wall, curb and/or gutter, breakwater (either salt or fresh water), underground or field-constructed above-ground storage tank and connected dispensing equipment, water system, drainage structure, filtering system (including septic or waste disposal systems) or swimming pool shall be deemed a structure permanently annexed to the freehold, and all shrubbery, earth, sod, sand, gravel, brick, stone, tile, pipe or other materials, together with the reasonable rental or use value of equipment and any surveying, grading, clearing or earth moving required for the improvement of the grounds upon which such building or structure is situated shall be deemed to be materials furnished for the improvement of such building or structure and permanently annexed to the freehold.
Va. Code § 43-2