Floor plan planning shortly before submitting the building application

So: the 201 cm is a typical rough opening dimension, no one familiar with construction would think that this is a passage dimension. It is measured, as with windows, from the top edge of the "parapet" to the bottom edge of the lintel.

The 15 cm is a prescribed dimension for the threshold on the outside. The ground floor ceiling is an interface to the "outside" under the terrace and therefore requires more insulation than on the inside towards the interior of the inhabited upper floor. It is logical to expect that the threshold inside will not be lower than outside.

This threshold is measured up to the bottom edge of the finished wall opening, but not up to the top edge of the lower door frame profile. The general contractor rightly says that this is designed for stepping over, not stepping onto.

It would have been reasonable here to inform the client during the window selection about the option of a flat threshold instead of a normal frame profile at the bottom of the door opening. However, this is a consulting error and not a construction defect.

If I deduct 15 cm threshold from the top edge of the finished terrace, 10 cm more insulation outside, and 8 cm frame profile, then I come to 33 cm effective foot lift height without exceeding the promised dimension.

I do not want to exclude that judicial ignorance could also interpret 15 cm promised foot lift height differently, but that would only be achievable under optimal laboratory conditions, and only then at full moon and without the mettwurst tax.

How is the builder supposed to know as a layman that the threshold is meant from outside to inside for the situation and not the other way around? I would never, ever have signed that!

That it is higher on one side than on the other, I basically have no problem with that, but then the specifications in the contract (15cm) must surely be the maximum threshold and not the side where the threshold is lower.

If I calculate 15 cm threshold from the top edge of the finished terrace plus 10 cm more insulation outside and 8 cm frame profile, then I come to 33 cm effective foot lift height without exceeding the promised dimension.

That's totally insane; who wants to live like that? And why on earth would anyone offer me something like that?

It would have been reasonable here to make the builder aware during the window selection of the option of a flat threshold instead of a normal frame profile at the bottom of the door opening. However, that is a consulting error and not a construction defect.

In the end, whether we (hopefully) get away with a planning error or a construction error doesn't matter to me. I find the argumentation that the lawyer has developed quite coherent. He basically assumes both.

Let's wait and see.

I have something else to guess about. In the execution plan, the front door element is listed as 4.125m x 2.36m.

If that is also a rough construction dimension, I wonder why I am given a dimension of 4.09m x 2.39m for the front door that has not yet been installed. Sometimes doors/windows are smaller than the dimension in the plan, sometimes they are larger... I think, in this case, the height is not a problem but it is still interesting.

Interim conclusion from the whole story - one should always agree on all windows exactly in the contract? What use is a rough construction dimension if you don’t know how wide the frame is, etc.?

The fixed window element in the dressing room, for example, has about 10cm more glass surface width than the patio doors. As a layman, you don’t realize that beforehand when everywhere the same dimensions are stated. For the builder, the glass surface area is what matters. Up there we now have three different widths of glass. The utility room because of the emergency exit—I don’t know why this width was not proposed everywhere—then the width of the bedroom and bathroom exits, and the fixed element in the dressing room with yet another width. So if I had known that, my aim when signing the contract would have been to have four elements, all with the same glass surface width. Why should I care about the rough construction dimension? I care about the clear height and the clear width!

but then the specifications in the contract (15cm) must surely be the maximum threshold and not the side where the threshold is lower.

You should have asked why a threshold at all. Apparently, you did not understand its purpose. Of course, it has to be that high on the outside and then doesn't matter inside. Inside, it could have been 0 cm, but then there would have been a step in the floor slab.

How is the client supposed to know as a layman that the threshold is meant for the situation from outside to inside and not the other way around?

The threshold is against water ingress – not in the flow direction of an overflowing bathtub to the terrace, but in the flow direction of a fully watered terrace to the dressing room. Logic should also be expected from a layman. You asked too little at this point. You order cream cakes from the confectioner, not from the bread baker. You made the fundamental mistake of demanding an architect’s house from a general contractor. That is a gamble :-(

If this is also a rough construction dimension, I wonder why I am given a dimension of 4.09m x 2.39m for the not yet installed front door. Sometimes doors/windows are smaller than the dimension on the plan, sometimes they are larger....

I am not in the mood right now to check this in the plans. One possible explanation is: here the lintel could also be a stop, therefore the frame rests against it at the top and laterally there is no stop, but the usual installation gap.

God alone knows why this width was not proposed everywhere,

Oh, should I not have proposed any leveling there?

Why do I care about the rough construction dimension?

Because it is the decisive dimension. The rough builder comes before the window installer. So the dimension in which the rough opening is to be made is needed first. And how tolerances are used up is not known beforehand. A house is not built in a CNC milling machine but is constructed by rough workers.

Oh, shouldn't I have suggested an equalization there?

I meant the planner.