What structural changes can I make without authorisation? (Author: Karin Rezar) We have 9 different building regulations in Austria, which means that there are corresponding differences in the regulation of structural changes or alterations. For this reason, the term "structural alteration" should be used with caution. According to the Vienna Building Code, structural alterations are to be included in building projects requiring authorisation. This includes all changes or repairs to buildings that have an impact on strength, fire safety or neighbouring rights or change the external appearance, room layout or room designation. This includes, for example, changes to window openings or the addition of balconies. If the changes do not involve any significant external alterations to the building or do not affect the rezoning of flats or the creation of parking spaces, authorisation in the course of a building notification is also sufficient. So what can you change on an existing building without authorisation? If you consider the aforementioned changes requiring authorisation, not too much. If, for example, rooms inside a building are changed in such a way that load-bearing walls have to be demolished or altered, these changes must be authorised. Provided that this change to the rooms does not result in more space and therefore no change to the parking space obligation, a building notification is sufficient. Such changes to the interior of the building would only be exempt from authorisation if they relate purely to the maintenance of a room, such as the renovation of a bathroom. Applied to the external appearance of a building, the possibilities and the associated building law measures can be explained using the example of a window. If you want to replace the windows of a building and change the size or appearance (colour, glazing bars, etc.), this is a structural change that requires a permit. However, if, for example, only the windows of a building are replaced with new windows with the same appearance in the course of a renovation, this can be done without authorisation. In this respect, you may only make changes to buildings or parts of buildings without a permit if they are to be regarded as "superficial maintenance" and do not change the external appearance.