Calculation of floor area ratio land area

Dear forum members, how do I calculate the exact floor area ratio in sqm of my property? More precisely, I am also interested in the 50% exceedance for path, driveway, etc.

My property is 500 sqm in size, and we have a floor area ratio of 0.3. Ergo 150 sqm.

Now my house has 80 sqm floor area, the terrace is supposed to have 40. That means 120.
120<150 O.K.
Now to the actual question, the 50 percent exceedance refers to the total floor area ratio, right? So 150x1.5 = 225

225-120 (house and terrace) makes exactly 105 sqm for driveway and path?
Or?
Thank you very much

Interesting!

Do I have to register the exceedance with the building authority?

We are extremely close to the limit with our planned paved area...

225-120 (house and terrace) makes exactly 105 sqm for driveway and path?

Correct, unless the development plan was publicly displayed before 1990 (but then the ancillary facilities do not count at all) or overrides the regulations of the land use ordinance.

Do I have to report the exceedance to the building authority?

No.

Interesting! Do I have to register the exceedance with the building authority? We are extremely close to the limit with our planned paved area...

That's exactly how we feel too. Or rather, we are too close. You don't have to register anything, but a letter might still come ^^

There are also plasters that do not have to be calculated with 100%, just as a side note.