ᐅ Wallpaper or plaster? Which is better for a new build?

If the wall should be vapor-permeable, you shouldn’t use any fleece at all, but apply dispersion silicate paint directly onto the plaster. I find it quite illogical to introduce an organic material like fleece and adhesive into a moisture-regulating wall.

Sure, the painter’s fleece is not as impermeable as fiberglass or dispersion paint. But it is still 3 to 5 times less permeable to vapor than silicate paint applied to bare plaster.

Sanding (if needed), painting, done.

@Tolentino Thanks for the tip, I will keep that in mind.

@xMisterDx How important is maximum vapor permeability? Painter’s fleece is also vapor permeable, but having the walls plastered and then painted is probably more expensive than wallpapering with painter’s fleece, right? The walls would need to be finished at least to a good quality level Q3 or Q4.

Which wall paint should we use with painter’s fleece? Ideally silicate paint to reduce the risk of mold? Of course, assuming proper ventilation.

Gooosee159 schrieb:

How important is maximum vapor permeability? Painter’s fleece is also vapor permeable, but having the walls plastered and then painted is probably more expensive than wallpapering with painter’s fleece, right? You would need at least a good quality Q3 or Q4 level of joint filling on the walls.

Experts and knowledgeable amateurs who have read a bit have been debating this for decades. The fact is, your entire wall construction, with plaster, filler, primer, and silicate paint, will have an sd-value of about 0.03 m (1.2 inches). With a little less filler, but primer, paste, and painter’s fleece, it might be around 0.05 to 0.07 m (2 to 3 inches). According to standards, anything under 0.5 m (50 cm / 20 inches) is considered vapor permeable. So you are still miles away from that limit.

Still, the MrDx type here will soon predict a mold apocalypse. That is obviously nonsense in the extreme. The majority of people used to live in apartment blocks where dispersion and even latex paints made the walls quite airtight, yet most of those apartments did not have mold problems. By now, most dispersion paints are also classified as vapor permeable according to standards (sd-value < 0.5 m). Everything else is secondary.

There was also a post somewhere calculating how much moisture a wall can actually absorb (and then release later), and the absolute volume just didn’t add up without ventilation. Unfortunately, I lack the expertise to provide a proper proof here myself. But maybe you can find the text I mean with some good Googling.

Gooosee159 schrieb:

What type of paint should we use on painter’s fleece? Silicate would be best to reduce the risk of mold, assuming good ventilation, of course.

Yes, you can use silicate-dispersion paint; it is highly alkaline and helps prevent mold growth quite effectively. To prevent mold, the main thing is to heat and ventilate properly.

In my opinion, a high-quality filling job is more expensive than wallpapering with painter’s fleece, but this can vary, for example, if you have free or very cheap access to filler material or professional labor. Painter’s fleece itself is definitely a cost factor.

I would argue that especially with DIY work, the final result is much better, since at least I can’t manage straight, even joint filling over entire walls very well.

@Tolentino Yes, I also think it’s exaggerated, and paintable fleece is probably vapor-permeable.

None of my acquaintances, whether they live in rented apartments or houses, have ever really cared about how vapor-permeable the wall is, and there is no mold in any of those cases.

Yes, if you do the work yourself, paintable fleece will definitely give a better result than just filling.

Should I ask again what is cheaper with the painter: paintable fleece or just filling (if he only uses our filler compound? We got it for free)?

If the walls are just plastered, small cracks that appear during drying of the new construction will also become immediately visible. The paintable fleece would cover these at first.

How likely is it that such cracks will form in the wall? All the people I know who have built a house had some cracks (including some who tore wallpaper). The developer also warned against just plastering the walls, as such cracks can occur.

We are only talking about cracks that don’t affect the structural integrity (and according to my acquaintances and the developer, these are normal).

Hello,

May I briefly use your thread for my purposes?
I would like to start some preliminary interior work on our house, but I am already struggling with choosing the right materials.

1. The joints between the precast concrete ceiling panels need to be sealed. What should I use for this? Rotband? The selection is somewhat overwhelming.

2. Our walls were plastered with gypsum plaster at Q3 finish. We would like to repair small areas, lightly sand, and then paint. Do we need to apply a primer or plaster sealer beforehand? What type of paint is best for gypsum surfaces?

@Gooosee159 Yes, that is normal wherever different materials meet, for example: drywall on masonry, masonry on concrete. Paint fleece can cover these small (shrinkage) cracks well.
@LastCookie Strictly speaking, you should use cement mortar (e.g. R&R mortar) to stay as close as possible to the surrounding material, but we used Rotband and after one year I don’t see any problems on the ceiling, especially since we also have paint fleece there.
For concrete, you need a primer; there are many combination products available, just read the labels or ask a professional advisor.
For paint, I recommend silicate dispersion paint. It is easier to apply than pure silicate paint, but still highly alkaline and somewhat more vapor permeable than standard dispersion paint.