Thin plaster vs thick plaster? When should you use what?

[KJD]

When do you know if you can apply thin plaster or if you need thick plaster? Is it for load-bearing or for appearance? I might plaster indoors in a basement bathroom, on lightweight concrete - I've seen that Weber has a product "Weberbase 138 tunnputs" which might be suitable. I have some cracks in the lightweight concrete, so I'm wondering if I need mesh?

 

[Plupp 405730]

This is how Weber says you should do:

On aerated concrete, the plaster layer is reinforced with webertherm 397 EF mesh to counteract cracking. In these cases, Base 138 is applied in two layers, a first layer on the substrate 4-5 into which the fiberglass mesh is worked so that the entire mesh is enveloped by the mortar. No earlier than the next day is an additional layer of 2-4 mm applied, which is floated to the desired texture.

 

[KJD]

Here's what Weber says you should do:

On aerated concrete, the plaster layer is reinforced with webertherm 397 EF mesh to prevent cracking. In these cases, Base 138 is applied in two layers, the first layer against the substrate 4-5 where the fiberglass mesh is worked in so that the entire mesh is enclosed by the mortar. Earliest the next day, an additional layer of 2-4 mm is applied and floated to the desired texture.

Ok, I see. I'll do it on the doM (two) walls that already have visible cracks. Thanks