Small cracks in newly plastered wall

[herge]

Hello,

I'm working on fixing up the basement and have applied 8-10mm of plaster (Finja B-bruk) on two of the interior walls. Now that it has started to dry properly (3 days since plastering), I see that small cracks are forming here and there. What could be causing this and what should be done? They don't look like any "serious" cracks; they are short and thin, about 4-8cm in a couple of different spots. Should I just paint over them? I didn't use any reinforcement as I was told it wasn't needed on Leca walls indoors.

 

[emwpoma]

I had a chimney plastered a while ago and, just like you, it got some small cracks in the plaster. They disappeared when I painted the chimney and everything looks good now.
Now, I'm not an expert in the area, but this is just my experience.

 

[oceanis]

If there are small fine cracks, they are most likely so-called shrinkage cracks, probably due to drying too quickly. To avoid this, you should make sure to pre-water the wall and continue to water the surface of the plaster while it sets. Normally, this type of crack does not affect durability unless you have "bom," meaning the plaster has not adhered to the substrate. You can tell by tapping on the surface.

If there are noticeable cracks, you can fill them with mortar, but many of the hairline cracks will be covered when you paint.