Acrylic joint ceiling / wall in new construction - When to seal?

Our drywall installer advised us to do the acrylic joint after 6 to 12 months. We will do it now, after 4 1/2 years.

Acrylic is unfortunately not elastic enough in the transition between the rigid wall and the slightly movable wooden ceiling. It will always crack. That's why a molding is used. Different with concrete ceiling, there it works. An elastic alternative to acrylic would be MS polymer. Paintable, unfortunately more difficult to work with and more expensive.

Acrylic is unfortunately not elastic enough at the transition between rigid wall and slightly movable wooden ceiling. It will always crack. That's why a molding. Different with concrete ceiling, there it works. Elastic alternative to acrylic would be MS Polymer. Paintable, unfortunately more difficult to work with and more expensive.

Yes, that's right. I remember that they mentioned something about a molding. I tuned it out - I don't want a molding!