Primer before plaster? C Mortar plaster

[Elbk]

in the same boat as you., I have concrete block, completely bare outer wall in the basement, did you plaster without a primer? what does it look like today? ARE THE JOINTS BETWEEN THE BLOCKS VISIBLE?

can you just put on reinforcement mesh and use weber 135 c plaster mix and plaster 2-3 cm, then the joints won't create stripe walls as a thick layer of plaster is applied, has anyone tried or has experience with that?

how did it turn out for you?

 

[Ernfrid]

in the same situation as you, I have concrete hollow block, completely bare exterior wall in the basement, did you plaster without priming? how does it look today? DO THE JOINTS BETWEEN THE BLOCKS SHOW?

can you just put reinforcing mesh and use weber 135 c plaster mortar and plaster 2-3 cm, then the joints won't show since a thick layer of plaster is applied, has anyone tested or has experience with that?

how did it work out for you.

We put mesh and primed with B mortar I believe. But when it's concrete hollow block you can even use A mortar only if you want to.

Instead of painting, we colored the plaster and just applied a primer

No, you apply in stages and scrape off, so no seams are visible

 

[Elbk]

Okay. Do you have a photo of how it looks unpainted but colored and primed? Do you mean you have primed the wall and left the fine plaster texture as a decorative wall?

Hmm So you mean the joints between the concrete stones won't be visible when it gets damp, so-called striped checkered walls that people talk about if you haven't primed. Instead, it won't be visible because you apply layer upon layer of plaster 2-3cm, you mean, and it won't show?

However, I don't understand why there's a rule of thumb to prime. It's probably an extra sales argument, right?

 

[Ernfrid]

Okay. Do you have a picture of what it looks like not painted but colored and primed? 😉 Do you mean you've primed the wall and kept the fine plaster structure as a decorative wall?

Hmm So you mean the joints between the concrete stones won't be visible when it gets moist, the so-called striped checkered walls people talk about if you don't prime. But it won't be visible because you apply layer upon layer of plaster 2-3cm you mean and won't be visible.?

However, I don't understand why there's a rule of thumb to prime. It's probably just an extra sales argument, right?

https://imgur.com/a/hfoFqaW

I haven't seen any striped spots, no. Yes exactly I wanted the color a bit more vibrant, even though it's gray.

You should prime, it won't adhere if it's too dry.

 

[Ernfrid]

[link]

I haven't seen any striped spots, no. Yes, exactly, I wanted the color to be a little more vibrant, even though it's gray.

You should prime, it won't adhere if it's too dry.

The primer is a silicate primer, it makes the wall a bit mottled.

 

[Ernfrid]

The primer is a silicate primer, it makes the wall a bit mottled

But I went with the cheapest plaster I could find and bought pigment to mix in.

 

[Elbk]

What did you start with?

 

[Ernfrid]

What did you use as a base?

A base if I remember correctly, did the rest in C

 

[Ernfrid]

What did you use as a base?

You can apply very hard usage directly on hollow blocks as mentioned, A, for instance, shouldn't be a problem.

But you often find C mortar cheaper. If I redid it, I would probably go with A or B all the way through.

Remember to fasten the mesh properly. We used anchors and screws.

And if you don't like it to become mottled like a lime wash, paint everything with silicate and measure each batch in the mixer to get the right amount of pigment—it's quite nerve-wracking but cheap.

 

[Andy82]

I am going to plaster, alternatively coat, my basement interior walls which consist of concrete blocks and lightweight concrete blocks. Mainly to seal for the installation of a mechanically installed wall.

Right now, I am filling in the joints and have used plaster/mortar C. When I plaster, a C mortar or lime mortar is used if I want the plaster to breathe. In this thread, A or B mortar is recommended as a primer....is that a bad idea in my case? Should I just use C mortar? You shouldn't apply a stronger mortar on top of a weaker one....and in my case where I have repaired/fixed joints with C mortar. Am I then bound to C mortar or does the priming not matter?

When priming, should I use a more slurry-like consistency to splash onto the wall?

Is it a disadvantage to just coat? A Platon membrane will be placed against the wall and on top of that, studded walls. You want to avoid any plaster falling down over the years (even if it's not visible, but maybe it could impair the properties of the ventilated system?)

 

[neo11]

You should use c mortar 3 mm, internally. Externally, a or b mortar is used below ground and for the base.
30 cm above ground externally, you can also use c mortar.
If priming, it should be looser than porridge.

 

[Andy82]

You should use c mortar 3 mm, internally. Externally, you use a or b mortar below ground and for the base.
30 cm above ground externally, you can also use c mortar.
If you are going to prime, it should be looser than porridge.

Thank you
…and you should always prime if the surface has not been plastered before?

 

[neo11]

Well, primarily on brick. But the walls must be "dust-free" beforehand, otherwise you have to pre-water to bind the dust. But don't water too much, concrete blocks don't absorb anything.