Exit terrace doors and external window sills, floor-to-ceiling windows

I need your help regarding the topic of exits. We have 4 floor-to-ceiling elements on the ground floor. Two of them are patio doors + fixed glazing, the other two are without doors. Currently, there is only liquid membrane sealing downstairs, but no windowsill yet. Today the plasterer came and asked me how I plan to proceed and by when, so that he can then make the top coat accordingly. Luckily, I had already given it some thought last week.

There is 13cm space under the roller shutter rail, I would then put 8cm XPS, 3cm granite slab at the elements with doors (2cm at those without doors) and the rest for foam/mortar/slope. Is that sensible or is that planned too tight? Currently, I am also unsure whether it is better for a layman to do it with well foam or with mortar. The advantage of foam is that you can simply cut off the excess, with mortar it would probably be easier to model the slope? It is also important to me that no water is absorbed, hence the consideration of using well foam. As far as I can see, the windowsills are delivered in multiple parts from about 2m anyway. The elements with doors are very wide, one is 3m and the other 3.5m, does it make sense to combine them from pieces with 2cm and 3cm thickness or will it become a big hassle for savings of 50€?

And one more question regarding the surface. Some stones are only available polished. Is that a serious problem in winter or when wet and should we only choose ones that are flamed and brushed?

I don't understand what you are planning. Is it the case that you have omitted the exterior window "sills"? Usually, this is done if you want to work paving/patio, paths, or splash protection directly into the reveal for a seamless transition. Without any fiddling. Is the photo your work? Is it supposed to be visible? Or what should be on it?

I haven't really given up on anything, but the construction description is not entirely clear, and the general contractor has already indicated that he doesn't see it as his responsibility ("they can put a stone slab or a metal sheet there"). And before I pay any extra charges for some laborer to botch it, I might as well do it cheaper myself. Originally, paving into the reveal was also my idea; that would basically be possible on the terrace too. The other terrace door leads to a small staircase directly into the garden, where there is no paving. That's why the idea came up to make it uniform now and use a stone slab everywhere. The photo shows the current state. Window on the base plate, in front the first row of stones insulated and everything sealed with liquid foil. I didn't do that.

What goes on the outside there? What do you want to put in front of the XPS from the outside in your planning? You can’t just leave it exposed like that. As Yvonne writes, usually the terrace goes there, or a step, if no terrace is planned directly at the house or not at all doors. We built steps made of granite stones at the exits because we don't want a terrace directly at the house. At the fixed glazing, our general contractor installed a windowsill, the same as at the higher windows. However, that was independent of the plasterer, who plastered normally, and then we added it later.

There are 6 granite stones with us, used as steps or door thresholds. Ideal for stepping out and placing things, e.g. hot pots in the kitchen. Installed by the landscaping gardener.

What do you want to put in front of the XPS in your outside planning? You can't just leave that open.

The plasterer would then plaster over it. In front of that, there will be a dry bed as a drainage strip. At first, I also thought I would do it after the plasterer is finished. But if he plasters it right away, that is of course even better and I don't have to worry about the transition.