Doors: drop-down floor threshold

Hello me again, a craftsman just installed a new door to our meeting room here. New to me, door with a drop-down bottom seal. Is it also worth it for a private home regarding drafts and noise??? about €30/door more?

Do you mean the door sill or a retractable rubber lip in the door? Probably the latter given the extra cost

Yes, you are right, such a rubber lip that automatically extends when closing.

You usually don't have this problem with the front door, as there is always a small threshold installed or a drop-down door seal. With interior doors, you can do this for soundproofing, but usually the door itself is already a weak point. And with a ventilation system, the whole thing is counterproductive.

I think that is done in companies for fire protection reasons, namely to keep smoke out of the stairwells in case of fire. We have that here in the company as well, but with us one door always causes problems and tends to scrape until the next repair.

For interior doors, you can do that for soundproofing, but usually the door itself is already a weak point. And with ventilation systems, the whole thing is counterproductive

In terms of sound, the seal is, in my opinion, the first effective measure. Additionally, you can then make the entire door sound-excited. Conversely, a sound-excited door without a drop seal is, in my opinion, not very useful.

In connection with ventilation systems, there are also sound-damping overflow valves or you guide the sound over the door frame or use the overflow drop seal in the door (the air is redirected twice here, hence the soundproofing while the door is still sealed to the floor). Suitable search terms would be, for example, "soundproof overflow element"; "soundproof inflow valve"; "Planet drop seal Mine-F" ...