How is the sealed area calculated?

Hello,

we are currently calculating the area that is already built on to find out how much we are allowed to build additionally.

I have a question: is everything counted 100% towards the built-up area, or are some things only partially counted?

The following areas are built on as standard.

House and garage are definitely counted at 100%.
Terrace with concrete stone terrace slabs probably as well.
Garden shed is certainly also counted at 100%.

But what about permeable concrete stone joint paving?
Are these possibly only counted at 50% because they are permeable?

I hope you can help me.

I hope you can help me

Unfortunately only to a limited extent, as this varies depending on the federal state and wastewater association. This is how it is with us in Central Hesse:

Thank you for the hint.

Does anyone know what the rules are in NRW?

Can no one help me with what the rules in NRW are or where I can find these rules to read? A second question would be whether raised beds also count as sealed surfaces.

Search for Baunutzungsverordnung = Baunutzungsverordnung

With us or rather I would generally understand it as follows: everywhere where rainwater can normally seep into the ground, it is not considered sealing. This applies to beds (including stone beds) and lawns. Edgings are also not considered as calculable area.