Building without a permit: What are the rules?

Questioner

Someone wants to build an extension of 150 m2 without a permit. The building area is larger than 300 m2, so a maximum of 150 m2 may be built on the backyard without a permit (according to the 'Public brochure on building without a permit' of the Central Government) This enlargement applies compared to the 'zero situation', i.e. the original main building, as it was built at the time in accordance with the permit granted. This means that not only the backyard area counts, but also the square meters of the extensions that were added to the main building later count when calculating the permissible building area. This can be interpreted in two ways: 1) only the built extensions without a permit compared to the zero situation count (i.e. a new zero situation is created by the granted permit) 2) All previously built extensions count (with and without a permit). What is the correct interpretation?

Lawyer

The building area is: 'backyard area as well as the land under the main building, excluding the land under the original main building'. This means that all additions, extensions and outbuildings must be deducted from the still buildable plot. It does not matter whether these structures were placed with or without a permit. Incidentally, it is not the case that 150m2 may be built on as soon as the backyard area is larger than 300m2. To calculate the correct surface area, I refer you to art. 3, under f Appendix II to the Environmental Law Decree: the surface area of ​​associated buildings, whether or not built with a permit, in the development area does not exceed: 1°. in the case of a building area smaller than or equal to 100 m2: 50% of that building area, 2°. in the case of a building area larger than 100 m2 and less than or equal to 300 m2: 50 m2, increased by 20% of the part of the building area that is larger than 100 m2, 3°. in the case of a building area larger than 300 m2: 90 m2, increased by 10% of the part of the building area that is larger than 300 m2, up to a maximum of 150 m2 in total, For example, if the building area is 350m2, 95m2 may be built on. If you have any additional questions, please let me know.