This line matters for sidewalk repair because DOT's transverse slope specification is measured starting from the building line and running toward the curb, so an improperly graded flag near this edge can trigger a drainage-related violation even without visible cracking. It's also the reference point for areaways, cellar doors, and other below-grade features that sit right at the edge of a building's foundation. Surveyors and contractors use the building line, together with the curb line, to establish the exact footprint a sidewalk reconstruction needs to cover.
← Back to Full Glossary