ᐅ Standard drywall panels for bathroom ceilings

Hello,

In our bathroom ceiling, standard gypsum plasterboards (GKB) from Knauf were installed.

Now, after everything is done (skimmed, holes for the spotlights), and the painter is on site, he pointed out that it would have been better to use the green, moisture-resistant boards (GKBI) instead.

When we asked the drywall installer who did the work, he said he checked again with Knauf and that these boards can also be used for "moderately damp rooms, such as bathrooms." Apparently, he already knew this and that's why he used them.

The painter, who also works in drywall installation, believes it would have been better not to do that, as yellow stains might appear over time due to humidity after showering.

Opinions online vary as well. Some say the green boards are just a way to make money, others say it doesn’t really matter on the ceiling since it's only important for splash water protection, while others argue that especially on the ceiling it is important to use moisture-resistant boards.

The technical specifications of both boards are the same, especially the "water vapor diffusion resistance factor," if that plays a role here. The only difference is that the moisture-resistant boards absorb less water.

What are your thoughts?

I can’t really say, but what paint color is your painter using in the bathroom? Can’t this be solved right away with a suitable coating that won’t discolor later on?

He just wants to paint the ceiling with latex, and that’s fine. It’s not like a swimming pool.

If you don’t operate a constant whirlpool or steam sauna in the bathroom, it’s not a big issue.
Still, it is standard practice to use the green moisture-resistant drywall panels in wet rooms, which is hard to understand…

I believe there are at least two or three prefab home builders who usually do everything in gray as standard.

A single-family house usually does not have a true "wet room."