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Calculating the BAF
The BAF expresses the ratio of the ecologically effective surface area to the total land area.
BAF = ecologically-effective surface areas ÷ total land area
In this calculation, the individual parts of a plot of land are weighted according to their “ecological value”.
Types of surfaces and weighting factors per m2
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Sealed surfaces
(Weighting factor 0,0 per m²)Surface is impermeable to air and water and has no plant growth (e.g., concrete, asphalt, slabs with a solid subbase)
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Partially sealed surfaces
(Weighting factor 0,3 per m²)Surface is permeable to water and air; as a rule, no plant growth (e.g., clinker brick, mosaic paving, slabs with a sand or gravel subbase)
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Semi-open surfaces
(Weighting factor 0,5 per m²)Surface is permeable to water and air, water infiltration and plant growth (e.g., gravel with grass, wooden cobbles, grass paving blocks)
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Surfaces with vegetation, unconnected to the soil below
(Weighting factor 0,5 per m²)Surfaces with vegetation that have no connection to the ground and less than 80 cm of soil covering
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Surfaces with vegetation, unconnected to the soil below
(Weighting factor 0,7 per m²)Surfaces with vegetation that have no connection to the ground but more than 80 cm of soil covering
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Surfaces with vegetation, connected to the soil below
(Weighting factor 1,0 per m²)Vegetation connected to soil below, available for development of flora and fauna
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Rainwater infiltration per m² of roof area
(Weighting factor 0,2 per m²)Rainwater infiltration for replenishment of groundwater; infiltration over surfaces with existing vegetation
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Vertical greenery with connection to the ground
(Weighting factor 0,5 per m²)Direct connection of the vertical greenery with the soil, supply with nutrients and water directly over the roots in the soil
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Vertical greenery without connection to the ground
(Weighting factor 0,7 per m²)
since December 2019**Vertical or horizontal vegetation on a wall without direct connection to soil on the ground, permanent planters supplying the vegetation areas, artificial irrigation
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Extensive roof greening
(Weighting factor 0,5 per m²)
since December 2019*Nature-like design of the roof surfaces with a substrate thickness ˂ 20 cm without artificial irrigation
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Semi-intensive roof greening
(Weighting factor 0,7 per m²)Mixture of extensive and intensive roof greening with a substrate thickness › 12 cm (depending on the chosen plantings), usually in combination with artificial irrigation
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Intensive roof greening
(Weighting factor 0,8 per m²)
since December 2019*Design of the roof similar to ground-based green areas with a substrate thickness › 15 cm, usually in combination with artificial irrigation
*) In December 2019 the surface types for vertical greenery and roof greening were differentiated and can be used for new BAF-landscape plans since then. The previously established BAF-landscape plans refer to the surface types before December 2019 and are valid further on in this version.
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Contact
Senate Department for the Environment, Transport and Climate Protection
Dr. Sebastian Hausmann
- Tel.:
- +49 30 9025-1254
District information on landscape plans
Concrete information on the calculation of the BAF for building plots that are included in a BAF landscape plan is provided by the respective responsible districts.