If this is not the case, the necessary fire protection must be retrofitted. Furthermore, the system of requirements has changed in recent years. Since the building regulations were changed in 1993, the rating is based on “metres above the ground of the highest lounge”. Previously, a distinction was made between four building types with counting of the floors. As a result, the public buildings and tall townhouses now often have higher requirements than before.
Free-standing buildings with up to two full storeys and up to two usable units used to have no requirements above the basement - like building class 1. Today, however, the basement must have fire resistance class F 30.
- Lined up buildings of the same size were given fire resistance class F 30 throughout, similar to building class 2.
- With three to five full storeys, walls with fire resistance class F 90 and ceilings with fire resistance class F 30 were sufficient. Most of the houses with wooden ceilings were built in this way, some of which were also built with considerable heights. From today's perspective, these buildings are rather problematic to look at.
- As early as around 1900, fire resistance class F 90 was required over five full storeys. These buildings are less of a problem today, because the target direction has not changed, although the requirements may be different in terms of technical details.