Distance between doors and floors 25mm

With us, it is generally solved differently for the necessary circulation for the mechanical ventilation. The doors have a maximum of 3-5mm of air at the bottom, but the door frame is specially milled on the inside at the top on both sides at the factory invisibly.

That’s how we will do it too. My cousin did it that way as well, it’s great. You don’t see anything and the function is ensured. Such a huge gap under the doors would also be an absolute no-go for me. A few millimeters are okay, but I definitely wouldn’t accept 2.5 cm either. That looks terrible. Our ventilation system installer gave us a calculation showing how big the gap under each door needs to be to ensure the smooth operation of the ventilation system. For the living and sleeping rooms, we have to leave about a 5 millimeter high gap under the door, I think (I don’t have the paper at hand right now), and for the bathroom it was 1.2 cm, I think. And even this 1.2 cm I find too much and would not have been an option for me, so we are now solving it with a small gap under the door and additionally with milling in the door frame.

We have also seen a calculation of how big the gap under the doors would have to be. However, these theoretical measurements are unnecessary in practice because the doors are not kept completely closed. The doors are opened again and again during the day or are open anyway.

Best regards
Sabine

There was no insight regarding the doors, therefore nothing in the report.

For you it is now too late, but for all future cases. The acceptance is practically a one-sided process of the builder or buyer. There does not have to be agreement on the protocol; whatever one wants to include in the protocol, one should do so. Ideally, one has paper and pen with them . And very important is the reservation regarding the rights to the known defects. And in any case, a (one-time, early) legal consultation is recommended when building or buying a house.

Our ventilation system installer gave us a calculation showing how large the respective gap under the door must be

First, exemplary that this calculation exists! But besides the gap between door and floor, there are other options:
- Overflow of the frame (as described here in the thread),
- Drop seals with overflow function,
- Special overflow valves, e.g. for the wall.
No one *has to* accept saloon doors if they have ventilation.

No one *has to* accept saloon doors if they have ventilation.

I agree. We do have the calculation, but we will still opt for frame ventilation (i.e. milling out the frame) because I want to avoid the huge gaps under the doors.

These theoretical measurements are unnecessary in practice, because the doors are not kept completely closed. You open the doors repeatedly throughout the day or have them open anyway.

Well, not in all rooms, but bathrooms, utility rooms, kitchens, study rooms, guest rooms, etc. are then closed now and then or many of them remain closed permanently.

We do have the calculation, but we are still relying on frame ventilation

The calculation only indicates the required free cross-section. A frame ventilation should also provide the required overflow performance.