ᐅ Doors: drop-down threshold seal

Hello again,
a craftsman just installed a new door to our meeting room. New to me: a door with a drop-down bottom seal. Is it worth it for a residential home in terms of drafts and soundproofing?
Around 30€ (about $32) more per door?

Do you mean the bottom threshold or a drop-down rubber seal on the door? Most likely the latter with that additional cost.

Yes, you're right. A rubber seal that automatically extends when closing.

With the front door, this is usually not a problem because there is always a small threshold installed or a drop-down door seal is used.

For interior doors, this can be done for soundproofing, but often the door itself becomes a weak point. With ventilation systems, this is usually counterproductive.

I believe this is done in companies for fire protection reasons, specifically to prevent smoke from entering the stairwells in case of a fire. We have the same setup at our company, but one door often causes problems and tends to scrape until it is repaired again.

Sebastian79 schrieb:
For interior doors, this can be done for soundproofing, but usually the door itself is a weak point. And with ventilation systems, it is counterproductive

In my opinion, the sealing is the first effective measure against sound. Additionally, the entire door can be made soundproof. Conversely, a soundproof door without a drop seal, in my view, is not very effective.

In combination with ventilation systems, there are also soundproof transfer vents, or you can route the sound above the door frame, or use a transfer drop seal in the door (this causes the air to be redirected twice, resulting in sound insulation while still sealing the door at floor level). Suitable search terms could be, for example, "soundproof transfer element"; "soundproof transfer valve"; "Planet drop seal Mine-F" ...