ᐅ Sealing a patio door. Which trade or specialist handles this?

Hello everyone, here is a picture of our patio door. Our neighbors sealed the outside with a black bitumen layer or something similar. Can anyone tell me which tradesperson would do this kind of work, or is it something you can do yourself?

Shell construction or the window installer

Then I'll ask about that right away! Thanks

That is much faster and cheaper to do on your own! Just last week, I sealed my garage door that way. Went to the hardware store, got liquid waterproofing for building sealing, and then applied it with a small foam roller—done!

I had it professionally done by a roofer/metalworker. For a lift-and-slide door (3m/10 feet) and a double door (2m/6.5 feet), the total cost was approximately 500€ gross.

But can I use metal sheeting to keep out water?

There will be a canopy above the door... I think a liquid-applied membrane might be better in that case... The insulation is already installed, should I remove it first and then reinstall it?