Building description and offer city villa 190m2

Regarding the podium staircase, I can currently share experiences. The staircase goes from the ground floor to the upper floor and then to the attic, so over 2 floors, and is 1 meter wide. The precast concrete part, including installation by the shell construction company, cost around €7k gross. Tiling the stairs and landings with 120x60 cm tiles cost about the same amount again. Stainless steel railing is around €4.5k including installation by the locksmith. As a DIY project, it is definitely feasible for around €2-2.5k. The staircase remains in exposed concrete look, as it is a staircase in a two-family house. Quite some € adds up for such a staircase...

How is the point about the ventilation system to be understood?

Maybe it’s different for you, but my consideration is: Standard interior doors are included in the price. If you use a controlled residential ventilation system, doors that are somewhat shorter are installed (because of the ventilation). These "new" doors then come with an additional charge.

doors that are a bit shorter are installed

They are simply shortened by 5mm or installed to fit directly. There are no extra-extra doors for that (unless you have a builder who calls out a very low price at the start and makes money through things like this).

They are simply shortened by 5mm or fitted directly to size. There are no extra-extra doors for that (unless you have a builder who quotes a very low price at the beginning and makes money through things like this)

I have to interject briefly, as I am about to order the interior doors. Is there a guideline or something written on the internet about how large the gap under the door should be if you have a controlled residential ventilation system?

There are recommendations. I did not change anything on the doors in my last two houses. There was a normal 5 mm gap at the bottom. But we were and are people who always keep all the doors open anyway. You can also implement ventilation openings above the frames.

No extra doors or special heights are needed for residential ventilation.

Thank you, I also think that this is sufficient. Otherwise, I looked around on the internet again. There are overflow seals which are installed at the top and optionally on the sides in the frame.

Anyone have experience with this?