Permeable traffic areas in the building application

That is very rough-and-ready from your company and usually works well. But read my example... then it doesn’t work well. Karsten

and the answer was that they always write water-permeable in the application - because the building application only concerns buildings like houses and garages.

Then they probably only build in a district where that always works well. Could be. Reading educates, and most municipalities belong to the second category. But if they write, Lawn stone twenty, Paving stone fifty, and Asphalt one hundred percent, then I would take that as a signal: "with us, they are strict." It is common that when chiseling off the tiles, the too thinly poured terrace crumbles at the same time, you simply make the new one a little bigger. You can probably assume that half of the conservatories created in a piecemeal manner are illegal constructions; harsh critics even count them entirely as part of the dark figure. Take a look at cadastral maps and then the aerial photos. By the way, building authorities sometimes do this as well, which regularly leads to trouble.

What speaks against permeable at all?

So our house construction company handled the building applications. We were not asked what type of paving or terrace we wanted to have -....
As if you don’t have to specify a terrace at all. Somehow this contradicts itself here.

What happens if you don’t specify a terrace and build one later. ...

I think your building application is no different from others, in that not just once, but several signatures from you are on these papers. That is then also binding. Even if you sign blindly.

Regarding the terrace: to my knowledge, the terrace counts as half? towards the living area. I might be mistaken, but in that respect the drawing in the building application makes sense.
Possibly you are touching the floor area ratio if you were to build a sealed terrace, and/or the building authority always includes the permeable terrace in the plan for exactly that reason. You can tell from your numbers whether that is the reason...

Regards, Yvonne

Regarding the floor area ratio etc., it should be irrelevant because everything counts there, even if it is lawn used as a driveway as far as I know.

That's right! How the floor area ratio must be calculated is stated in the Land Use Ordinance. The areas are to be determined without regard to the type of execution. Permeability is not mentioned here, but the possibility that the development plan can make deviating provisions. Hence the different approaches in the municipalities.

Your building permit is actually binding. In my opinion, you cannot just change something then.

Unless the change is exempt from approval.

Why should it be critical if something is stated and then done differently?

It isn’t in my opinion either, since an uncovered terrace in NRW is exempt from approval. Nevertheless, it must comply with all regulations. Only that you as the builder take full responsibility for it.

As far as I know, the terrace counts as half?

But not for the floor area ratio, unless the development plan makes other provisions. The floor area ratio is a science of its own, so unauthorized changes by the builder can indeed lead to illegal constructions.

In NRW, aerial images are often used to determine whether sealed surfaces correspond with the notices. After all, these have an impact on the amount of rainwater runoff.