Greening and design statutes valid from 01.10.2022 (explanation)
Statutes on the greening and design of developed properties within the city of Mainz (greening and design statutes) dated June 25, 2022.
The statute came into force on October 1, 2022, and regulates the greening and design of developed properties and buildings in the urban area of the city of Mainz. At the same time, the previously applicable statute on green spaces within the city of Mainz ceased to be valid.
The aim is to design the townscape with climate change in mind and to maintain healthy living conditions.
Explanation of the Articles of Association
Strengthening green infrastructure is also a key issue in Mainz, as it
- creates habitats for animals and plants, promotes biotope networking, and strengthens biodiversity.
- It promotes the binding of fine dust and carbon dioxide and produces oxygen.
- It helps protect the climate and counteracts climate change. Shading sealed surfaces prevents extreme surface temperatures, while evaporation from vegetation surfaces actively reduces the temperature of the surrounding air. Extreme heat and peak runoff after heavy rainfall are reduced.
- Contributes to improving the working and living environment. Green structures have a positive influence on the townscape and architectural design and shape urban structures. Planting trees breaks up the visual monotony of sealed functional areas and parking lots and structures them with green elements.
With its declaration of a "climate emergency" on September 25, 2019, the city council of Mainz commissioned the administration to update the green space ordinance. In accordance with Section 24 (1) sentence 2 and (5) of the Local Government Act (GemO) of Rhineland-Palatinate and Section 88 (1) nos. 3 and 7 of the Building Regulations (LBauO) of Rhineland-Palatinate, the city of Mainz is authorized to adopt a statute on the greening and design of developed properties.
The ordinance applies throughout the city to undeveloped areas of built-up properties, including underground open spaces of built-up properties (such as underground parking garages, etc.) and the external design of structures. The statute applies to projects for which a building application is submitted, as well as to projects that do not require approval under the LBauO and projects in the exemption procedure under Section 67 LBauO.
The statutes set out requirements for the design and greening of developed properties, front gardens, parking spaces, storage areas, flat roofs, exterior walls, and commercially used storage areas. The quality and timing of greening as well as any necessary replacement planting are also specified.
According to the statutes, all areas not covered by above-ground buildings and the open spaces of developed properties covered by underground floors must be completely greened, unless they are required for a permissible use. Access points, driveways, paths, areas for the fire department, and parking spaces must be limited to the functionally necessary extent.
Flat roofs and exterior walls must be greened. A so-called "modular system" is also used for greening flat roofs and exterior walls (see Fig. 1) in order to offer alternatives and enable individual solutions. As an alternative to greening flat roofs and exterior walls, there is the option of planting additional shrubs on the building plot. In the case of roof greening, intensive greening at a ratio of 2:1 is also possible as an alternative to the required extensive greening. These alternatives ensure greenery on built-up sites while allowing for greater flexibility and individual solutions. The resulting varied green structures—roof greening, facade greening, shrubs—are also urban design elements that structure, break up, and accentuate the spaces created. A combination with solar systems, especially photovoltaics, is possible.
The greening and design regulations also govern the planting of trees and shrubs. For every four above-ground parking spaces, at least one tree must be planted (see Fig. 2).
One tree is required for every 200 m² of land area not covered by above-ground buildings. In addition, 15% of the building plot must be planted with shrubs, provided that the planting does not conflict with any otherwise permissible use. Covered car/bicycle parking spaces and other parking/storage spaces (especially waste and recycling containers) must be greened. Commercial storage areas must be screened off from adjacent plots of land with other uses by shrubs. Both existing shrubs and trees and trees/shrubs to be planted due to other obligations (e.g., stipulations from development plans) are taken into account.
For climatic and design reasons, some uses and materials are also excluded for the entire urban area. For example, it is clearly stipulated that front gardens may not be used as work or storage areas and that fillings of gravel, crushed stone, and similar materials, lawn grid stones, and gravel turf, as well as flat coverings with fleece, foils, textile fabrics, and the like, do not count as greening. The creation of so-called "gravel gardens" is therefore no longer possible.