House and floor plan planning - First architect's plan is available

And/or you make a slatted floor on the terrace like in the cattle barn ;-)

Now I had to laugh. Almost fell off my chair. We have something like a slatted floor - well, so that you don't see anything and it used to be the cowshed.

as often when not specified the standard applies and that is with a threshold. Since you had to sample more price-consciously, it was probably clear to the seller what it would be and indifferent to a man.
Whether you can still simply reorder? By the way, I also have window sills at the threshold-less door.

I also believe that it is less about the threshold and more about not wanting to step down. And of course, you can align that with the terrace. Whether you build around the windowsill or not, I would depend on the windowsill (walkable or not?), personal taste, and the desired design of the terrace. For example, I am currently planning a terrace as a wooden deck, which is supposed to be at the finished floor level. The window frame remains below as an approximately 3cm threshold, and where the terrace is in front of the floor-to-ceiling windows, there is no windowsill. The terrace is supposed to go into the reveal. Whether I actually put a channel in there, I don’t know yet, since the terrace will be about 40cm above ground level. From my point of view, the slope of the terrace should be sufficient to drain the amount of water arriving on the terrace. And yes, I will not lay the boards tightly together, even though cow dung surely should not be able to fall through there either. Where there is no terrace (I still have three more floor-level windows), I will probably install walkable stone windowsills. There you will have a step to get into the garden...

We only have the joints between the slabs and a little more - maybe about 5 mm around the window sills. The slope has been sufficient so far. You just have to make sure that no standing water can form on the house wall.

Sounds interesting, could someone here explain exactly what you have to/should say during the sample selection process to get all windows floor-to-ceiling with the terrace?

The way Tolentino described it here (that the terrace flooring extends into the jamb) sounds like a very nice solution to me, what do you have to consider here (to be able to order it correctly during the sample selection)? For us, this would involve a lift/slide door, a fixed glazing, and two floor-to-ceiling tilt-and-turn windows. Is it possible to set this up with all existing windows?

It is important to seal the window reveal horizontally to vertically. Our expert was there specifically for that. It is probably more difficult with window sills.

We clearly stated which door must be without a threshold.

What else needs to be considered when the terrace height equals the top edge of the finished floor will be specified by the GU.

So completely flush, practically without a threshold from inside to outside, I lack a bit of the imagination for that, since the window sash has to press against some kind of frame to close tightly. And at least this overlap, in my opinion, is always present. You can certainly minimize it, but then all trades really have to work with minimal tolerances (from the shell builder to the screed layer to the tile/floor layer and of course also the window builder/installer and the landscape gardener). The fact that the terrace runs into the reveal just has to be managed by the landscape gardener or whoever builds the terrace. In this regard, correct sealing at the window connection must be observed. A very common point of dispute between the trades. Because theoretically, this can often be done by the window installer, the plasterer, the landscape gardener, or even the roofer (odd, but he knows a lot about sealing). It just has to be defined who should do it and exactly how (for which execution).

It is easiest if you already know for each window how you want it. Then the contractor can already incorporate this into his planning and a general contractor/main contractor simply chooses the appropriate subcontractor for the respective work. An architect takes this into account in the tenders.

It gets difficult if the terrace, as so often, is owner-performed work. Because then you can expect the other trades to do as little as possible...