Security doors - Which companies / which trade install them?

Thank you, I found what I was looking for with the term "Fensterbauer". :)

Mostly there are simply "door dealers" who do exactly that (no matter where they originally came from)

I meant: many plastic window manufacturers were or are carpenters – which is an advantage if a wooden door is desired: they can do that too.

Thanks, I found what I was looking for with the term "window manufacturer".

See, the good is so close ;-)

Hörmann or Teckentrup. They also offer installation through partner companies.

For WK 2 or 3, these are usually composite doors in a metal frame with a metal casing.

Mounted with wall anchors or the right screws, nothing gets through anymore - except a military projectile. ;)