Is the joint diffusion-tight or not?

[boojy]

I have just diffusion-sealed the windows on the inside of our house from 1985, it has concrete on the outside and studding on the inside. I've understood that the seal on the outside should not be diffusion-tight. Does anyone know if this seal is tight or not? It is elastic and almost like the old classic adhesive putty that was used in schools in the '80s 🙂

I'm wondering if I need to tear it out and replace it with something else?