ᐅ Placement and Installation of Movement Joints in a Drywall Ceiling

Hello everyone!

I’m new here and would like to discuss the topic of movement joints in drywall construction. I’m working on my old building from 1948, where two walls were removed.
So far, I have only installed ceilings in small, individual rooms. There were no cracks anywhere. Now, however, I’m facing a somewhat larger, more complex area (see picture), which I want to approach carefully as a skilled amateur with proper planning.

Question 1: Where should movement joints be placed here? I have marked my two suggestions in blue. Are both of these necessary? Context: I am installing 12.5mm (1/2 inch) drywall panels all the way to the walls, where I use a separation tape. So, I am not creating a shadow gap or anything similar at the edges. Wouldn’t the movement joint then have to be placed somewhere else? Or am I overthinking this?

Question 2: I must admit that I have never seen a movement joint “in the wild” before. How would you implement one? Completely separate the substructure (I’m using 30x50mm (1.2x2 inch) battens), finish the panel joints with edge profiles, and place a drywall strip on top that is only screwed to one side of the area?

Thanks for your help!

Hello,

your considerations are not unreasonable, but you should look at the joint placement not only from an aesthetic perspective but especially from a structural one. When you mention that two walls were removed, this suggests a change in the load-bearing behavior of the ceiling – gypsum board is sensitive to that. The blue lines (I have the picture in mind) would only make sense if they are exactly at the transitions between the old and new ceiling sections. Otherwise, they won’t help much.

The fact that you haven’t had cracks so far is probably due to the smaller surface areas, not because you perfectly separated everything. For larger areas over 15 m² (160 ft²) or lengths over 10 m (33 ft), an expansion joint is almost mandatory; otherwise, the material will eventually develop hairline cracks – even with the best decoupling system.

And yes, a proper movement joint is rarely visible because it is usually cleverly concealed or covered with a shadow gap profile. The important thing is that the substructure is completely separated. If you run a batten through the joint anywhere, you can forget the purpose of the joint. Also, the gypsum board strip should only be fastened on one side; otherwise, there will be no movement allowed.

The beams in the ceiling run from bottom to top in the picture and stop at the horizontal axis where I drew the horizontal blue line. From there, new beams continue upward to the exterior wall. That is exactly where the wall used to be. The beam ends were screwed into a wooden beam added in the attic. For this reason, it shouldn’t be a problem.

What about the vertical blue line? There used to be a non-load-bearing wall there. The longest distance is 9m (30 feet) to the opposite side of the house. My online research showed that boards up to 10m (33 feet) can accommodate movement of up to 10mm (0.4 inches) when temperature and humidity have their maximum effect. I think that’s quite reasonable.

So you probably have a wooden beam ceiling. I personally have no experience with that. So far, I have only installed substructures and drywall on concrete ceilings. Would a painter’s fleece / non-woven wallpaper not be sufficient in your case for bridging cracks?