Floor area ratio; § 19 para.4 Building Use Ordinance - experiences?

Thank you

She made use of §3 with this one, for your area WA1 under 3. Specifically means: You do not need to include the access road to your house in the floor area ratio I.

Does this then only apply to "Pfeifenkopfgrundstücke"? All other plots then do not have this?

If you fully use the floor area ratio I with house and terrace, you still have 83.25m² left for garages, parking spaces, driveways, ancillary facilities (garden house, greenhouse, ...)

Does this then also only apply to the Pfeifenkopfgrundstücke?

The OP did not elaborate further on his thoughts

Facts:
Plot: 555m² * 0.3 = 166.5m² built-up area
Floor area ratio 0.3
Plot ratio 0.45
Not a Pfeifenkopfgrundstück

My thought was:
House: 11.5m * 13m = 149.5m²
166.5m² - 149.5m² = 17m²

Then only 17m² remain for garage, terrace, paving? ... that wouldn’t work

Except for the restriction "state," I see it the same way. And there is no real agreement about the access paths, which still leaves room for interpretation.

Thank you Escroda for the correction. At what level is it decided what belongs to the floor area ratio (I)? Can this vary from municipality to municipality?

Does this then only apply to "pfeifenkopf properties"? All other properties do not have this?

Yes.

Then only 17m² remain for garage, terrace, paving?

No. 17m² for the terrace, as it counts towards the main facility, i.e. the floor area ratio I. The areas of garages, parking spaces and driveways may exceed the floor area ratio by 50%, i.e. up to 0.45, which corresponds to a buildable area of 249.75m² for a 555m² plot. Example: House at 3m distance from the street, double garage at 5m distance Floor plan I: House+terrace=11.5m*13m+4m*4.25m=149.5m²+17m²=166.5m² Floor area ratio I: 166.5/555=0.3 => allowed Floor plan II: Floor plan I + garage + driveway + access path=166.5+9*6+5*6+3*1= 253.5 Floor area ratio II: 253.5/555=0.457 > 0.45 => not allowed, i.e. the garage must be shortened by 0.5m to 8.5m * 6.00m, for example. A second full storey is then not possible due to the floor space index. And the garden house is then also off the table.

At what level is it decided what belongs to the floor area ratio (I)?

At the federal level.

Can this vary from municipality to municipality?

Actually not, it is only sometimes interpreted differently. In my example above, I count the footpath to the house towards floor area ratio II (see City of Frankfurt). In Munich, an entrance staircase is counted towards the main facility, i.e. towards floor area ratio I. The privileging depends on the classification according to the Building Use Ordinance §14 outbuildings. Is the access path (driveways are explicitly mentioned as privileged in §19 (4)) a subordinate outbuilding or belonging to the main facility like the terrace? In practice, it usually does not come down to a fine line, so that in very few cases there has to be a dispute about it.