For many years now, Section 9 (2) of the Lower Saxony Building Code (NBauO) has stipulated that unbuilt-over areas of land must be green spaces unless they are required for another permitted use. Green spaces are characterized by natural or landscaped areas overgrown with plants. This does not completely exclude stone elements if they are subordinate to the vegetation.

This means that garden areas dominated by gravel, crushed stone, concrete or paving are not legally permissible without an associated, permissible and necessary use (e.g. gravel area as a parking space).

Gravel surfaces are not only inadmissible from a building regulations perspective, they also have other negative properties, such as

• Gravel surfaces heat up much more than green spaces in the summer months and cause additional heating.
• Gravel surfaces offer no habitat or food for insects in particular, but also for other animals.
• If large amounts of rain fall in a short period of time, sealed surfaces promote the occurrence of flooding if the existing rainwater drainage system is overloaded.

Further information on the negative effects of gravel gardens on the environment can be found on the website of the Federal Ministry for the Environment (see below).

Information and tips on insect protection and insect-friendly garden design can be found on the website of the Lower Saxony State Office for Water, Coastal and Nature Conservation (see below) or from nature conservation organizations.