According to Art. 55 Para. 1 BayBO, a building permit is required for the construction, alteration or change of use of a building.
Exceptions to this approval requirement are possible, e.g. procedural exemption according to Art. 57 BayBO or in the area with a development plan as an approval exemption procedure according to Art. 58 Para. 1 BayBO.
Period of validity: The period of validity of the building permit is four years in accordance with Art. 69 BayBO and can be extended by up to two years in each case on application, which must be submitted informally before the expiry of the four years.