What is a constraint?
A lien is a specific restriction to which movable or immovable property, whether public or private, may be subject due to its importance to the public interest.
A lien on a property obliges the owner to do or not to do something without first requesting permission from the competent public administration; the lien may even place limitations on ownership rights.
Types of constraints
Urban planning constraint
- Recognition constraint. Following an inspection (e.g., a site visit), the area is deemed at risk or valuable due to physical characteristics intrinsic to the land or the construction located there; they do not pose compensation issues.
The list of recognition constraints is subject to constant change, but the areas subject to this type of constraint can be summarised by referring to the following regulations:
Legislative Decree No. 3267 of December 30, 1923: hydrogeological restrictions, protection of land subject to erosion, denudation, loss of stability, flooding, woodlands, and forest areas;
Legislative Decree No. 1089 of June 1, 1939: protection of movable and immovable property of artistic and historical interest (now included in the Cultural Heritage Code);
Legislative Decree No. 1497 of June 29, 1939: landscape restrictions on the protection of natural and scenic beauty, which collaborates with the previous Law No. 431 of August 8, 1985, containing provisions on the protection of property of particular environmental interest (now included in the Cultural Heritage Code);
Legislative Decree No. 96/2005, Article 707, Navigation Code: airport restrictions.
Conformity restrictions. This stems from the need to protect specific objects of public interest and affects strips of land determined by the application of clearance distances from public facilities and places. These restrictions cease when the object that determines them is removed or modified. This category includes clearance restrictions for highways and extra-urban roads, railways, power lines, waterways, airports, cemeteries, military installations, drinking water wells, etc.
Urban planning and construction restrictions. These are imposed by urban planning instruments and are divided into:
Urban planning restrictions (listed above)
Construction restrictions
Procedural restrictions
Building constraint
Building constraints refer to parameters, indices, and requirements that regulate construction in various parts of the territory; below are some of the countless concrete examples:
IT = Territorial Building Index
UT = Land Use Index
IF = Land Building Index
UF = Land Use Index
Coverage Ratio
Permeability Ratio
Maximum Permissible Heights
Procedural constraint
Procedural constraints are the term used to refer to the requirement to prepare an executive urban planning instrument before requesting a building permit.