Baulinien

Baulinien are lines on planning maps or zoning documents that designate the permissible location of buildings in relation to streets and adjacent properties. They function as setback lines that constrain where a façade or other building elements may be erected. On a plot, one or more Baulinien may specify the front line along the street, as well as lines governing side and rear projections. Structures are typically required to be built behind these lines, which, in combination with other controls, shape the appearance and massing of a block.

In practice they are used in many European planning systems and are published in development plans or building regulations. Architects and developers must align new designs with these lines when submitting permits. Baulinien influence facade alignment, continuity of street walls, daylight access, sightlines, and privacy for adjacent properties.

Origins and evolution: The concept arose with 19th- and 20th-century urban reforms aimed at regularizing street frontages and improving urban form. Today, Baulinien are often implemented as digital layers in GIS-based planning tools and are enforced through permit processes.

Relation to other tools: Baulinien function alongside height limits, floor-area ratios, and setback requirements. They can also interact with municipal design guidelines and heritage protections to preserve historic street character.

See also Building line; Setback; Zoning; Urban planning; Building envelope.