Preparation is the key when it comes to functional air tightness

I´d say the detail on the photo is a very common sample of what happens to some parts of the building during the construction stage. Every involved trade adds a certain amount of dirt and mess, which ends in the layout as seen on the photo. Could you imagine how the window tape would look in case of being installed already?

There are two options now, to get the detail sorted:

No 1 - install the window board or worktop and everything is covered

No 2 - preparation and creating the functional air tightness layer

If you have seriously considered option no 1 as an alternative, you might should go back to the start and do some learning about the principles of building sealing and air tightness in particular.

The only solution that works in reality is, to clean the area, prepare the area and seal the area properly!

Please find some more details about the different stages down below