Why there are sixteen codes
Building regulations law is state law. The federal government has no legislative competence for the requirements placed on the individual building; it has competence for planning law, that is for whether and for what use building may take place at a location.
The conference of state building ministers prepares a model building code to align the state provisions. It has no legal force of its own, and the states have adopted it to differing degrees and at differing times.
A pattern follows that runs through the whole of German construction law. There is a shared system with divergent figures.
Where agreement is high
| Area | Degree of agreement |
|---|---|
| System of building classes | high, with individual departures |
| Concept of the special building | high in structure, divergent in catalogue |
| Roles of the parties involved | high |
| Underlying principle of separation distances | high |
| Fire safety objectives | high |
In these areas it is worth understanding the system thoroughly once. It transfers, and the departures then concern details rather than comprehension.
Where divergence is considerable
| Area | Nature of divergence |
|---|---|
| Depth of separation distances | factors from 0.2 H to 1.0 H by state and type of area |
| Narrow-side privilege | abolished in some states, surviving in others |
| Catalogues of procedure-free projects | considerable differences in scope and thresholds |
| Conditions for exemption from consent | differently drawn |
| Special building catalogues | differing thresholds and categories of use |
| Entitlement to submit | differing professional law requirements |
| Accessibility requirements | differing extent of obligations |
The first row is the most significant, because it directly determines the developable area. The article on separation distances covers the range.
The figures move
A second problem sits alongside the geographical spread: the temporal one. Several states have amended their building regulations law in recent years, in part considerably.
North Rhine-Westphalia reduced its standard separation depth to 0.4 H and abolished the narrow-side privilege at the same time. Bavaria recast its separation distance rules in 2021, also changing how roof and gable surfaces count.
A source without a date is therefore especially worthless in building regulations law. Anyone adopting a figure checks what year it comes from and which state it concerns.
A third level: the municipal one
In some states a further level is added. Bavaria, for instance, permits municipalities to set differing separation depths by local statute, within a statutory range and only for specified purposes.
The governing depth can therefore differ from municipality to municipality within the same state. A statement without naming the municipality is therefore incomplete.
Local building provisions and the provisions of the local plan sit alongside and may contain their own requirements. The branch on planning law covers that level.
An approach for an unfamiliar state
Seven steps establish a project in a state where one does not work regularly. They are to be taken in that order.
- Obtain the current version of the state building code, with the date of its last amendment.
- Determine the building class using that state's definitions rather than the model code's.
- Assess special building status using that state's catalogue and thresholds.
- Determine the procedure, including whether procedure-freedom or exemption applies.
- Calculate the separation distances, with that state's factor, its definition of H and its rules for roof and gable surfaces.
- Check the municipal level, that is the local plan, local building provisions and any statutes.
- Clarify entitlement to submit, including provisions for professionals from other states.
The fifth is the most demanding and the one where transferring from another state most often fails. It concerns the separation distances.
What cannot be transferred
Three points warrant an express warning, because they appear plausible and are wrong. All three concern quantities that do not transfer between states.
| Warning | Where the error lies |
|---|---|
| The separation distance factor | it differs not only between states but within a state by type of area |
| The catalogue of procedure-free projects | a project requiring no involvement of the building authority in one state may need consent in the next |
| The definition of H | how roof surfaces and gables count follows its own rules, and changing it affects the whole result |
What follows for cost work
The comparison across states has a consequence rarely reflected in cost benchmarks. It concerns the comparability of projects across state boundaries.
The same building task can generate different costs in two states, because developable area, fire safety and accessibility requirements and procedural effort all differ.
Anyone working with benchmarks should therefore know which states the underlying projects come from. The article on regional differences in construction costs covers the cost side of this relationship.
Related articles
This article reflects the position of the rules at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.