Lines/Shadows in Ceiling (Plasterboard)

[Leo_J]

We have had craftsmen here who have installed a new ceiling on the ground floor with spotlights. The new ceiling flows through 2 rooms totaling about 70 sqm. Now, after about 1.5 months, clear shadows/lines have appeared in the ceiling at the joints between drywall panels. We see this in about 10 places and have now asked the craftsman to come back and look at this.

I don't know how tightly they have spaced the joists or what type of drywall they have installed, but they have at least staggered the panels (that is, the seams are in slightly different places, not a long line through the entire ceiling). The joists are mounted against the wall as well as on the old ceiling (so we have about 8 cm lower ceiling height now).

What is the cause of this? Have they spaced the joists too far apart, attached the panels poorly, done a poor job with the plaster, used the wrong materials/products (mainly thinking of plaster, I read/heard somewhere that there is some sort of plaster glue or whatever it's called) or what?

How should this be fixed, does it involve replastering/sanding/painting the entire ceiling or do you have any other advice? I'm considering bringing in another craftsman for their assessment, as I don't fully trust the first craftsmen.

HELP!

 

[lagre]

Have experienced the same thing. It can be tricky to get it completely smooth without cracks and shadows, especially if it's a large area with strong light exposure. My own experience is that if you use paper tape and mainly gypsum plaster to fill the joints, you get a much better result than if you use fiberglass tape and only joint compound.

 

[Leo_J]

Ok, thank you very much. I have also read that paper strips are preferable. Right now I am considering simply waiting another 6 months and then bringing in the craftsmen to fix the problem. I expect that the roof/framework will have settled by then and the wood won't move anymore. What do you think about that?

 

[OHE]

Unfortunately, plaster ceilings can appear as you describe even if the boards are correctly installed and the right strips have been used. Naturally, the risk of cracks increases if the installation and painting haven't been professionally executed. It's difficult to inspect the painting afterward without damaging the ceiling. However, you can check the spacing of the studs with measuring equipment, and if the center-to-center measurement is incorrect, you have something concrete to report to the contractor.

Assuming the boards haven't been completely misinstalled, the best course of action might be to stretch fiber felt on the ceiling and repaint.

Good luck!

 

[anaitis]

I assume it's a wooden house?
If so, one must remember that wood can have relatively large seasonal movements.
This becomes more noticeable the greater the length affected.
What I'm trying to say is that your craftsmen may not have made a mistake, but the phenomenon you observed is probably unavoidable under the prevailing conditions.

Fiberfilt is probably also my best advice.

 

[Leo_J]

Thank you very much. I was also considering that seasonal dependencies have a significant impact since we live in a wooden house, and it has been extremely cold now, for example. This strengthens my theory that we should wait about 6 months or so to address this (with fiber blanket as you say). Then there is no guarantee that it won't happen again, but I would like it to "settle" right now before we address it.

The work was done by professionals, and I can't see it being poorly done. But I will check the spacing of the beams.