How to fix perpetual plaster peeling on a concrete porch?

[kok07]

We have a porch with an accompanying stair. The porch has a small balcony above the platform but is exposed to rain. The platform is made of lecablock, with cast concrete on the platform. It is plastered with b-bruk. The stairs are fully cast in concrete. The base is painted with Beckers base paint (acrylate). The problem is extensive plaster detachment on the porch, despite several attempts at replastering; the stairs have no problems. The question is how this can be resolved?

Ideas:
1. Moisture barrier/moisture-repellent paint on horizontal surfaces and a ledge to remove moisture. Plaster and paint as before.
2. Use another type of plaster/paint.
3. Combine 1 and 2.

Any suggestions on what can solve this Sisyphus problem?

Thankful for your thoughts

 

[jonaserik]

I would probably install a slightly rough frost-resistant tile. Moisture seeps through and down toward the concrete, then it peels away, either by peeling paint or by freezing and breaking in the winter. It looks like there is plenty of space under the panel. Remove everything so the concrete is exposed, then wire brush everything, vacuum. A couple of layers with cold asphalt as a sealing layer and, most importantly, apply an asphalt felt in the angle towards the house, so no moisture can come against the house. Finally, mix fine sand with the asphalt, so the surface becomes like a fine sandpaper. The tiles are set with adhesive suitable for outdoor use and should be fully smeared underneath so there are no air pockets. Tiles are available with cut edges and can be laid edge to edge, with no joint in between. But definitely not a winter job.

 

[kok07]

I would probably install a slightly rough frost-proof tile.
The moisture seeps through and down to the concrete, then it releases, either by the paint peeling off or freezing in the winter. It looks like there's plenty of space under the panel. Scrape everything away so the concrete is exposed, then wire brush everything, vacuum. A couple of applications of cold asphalt as a waterproof layer and especially apply an asphalt felt in the angle towards the house, so no moisture can reach the house. Finally, with the asphalt, mix in fine sand, so the surface becomes like finer sandpaper. The tiles are set with outdoor adhesive and should be fully smeared underneath so no air pockets form. There are tiles with cut edges that can be laid directly against each other, no joint in between. But not a job for the winter.

Thank you, Jonaserik! Do you think it would work just as well to lay a cement-based layer on top of the asphalt felt (like leveling compound), so it matches better with the stairs?

 

[jonaserik]

Will probably resolve itself as well. You say it matches the stairs. The next project will be to do. Tiles on the steps, hence a bit rough, can become slippery from ice/snow/water. Otherwise, talking to a tiler is probably not a bad idea, to get more information about the execution.

 

[neo11]

Feels like the problem arises because water is leaking into the plaster from above.
We are only talking about the entrance "square" and not the rest of the base, right?
I would chip away the B mortar and plaster with Cement mortar A instead.
It would handle moisture better, but I can't guarantee anything.
I guess it's plastered all the way up, outside the concrete, even if it's leca under the slab.
But you would still want a metal sheet on top, like a flashing on the 3 outer sides, a bit in.
The tricky part will be the inward finish, making it look nice.
The choice of color is not wrong, usually use alcro sockel,
but the same owner as beckers, so the same content in the can.

 

[Carl Johansson]

Water both erodes and frost-splits the plaster, to the right of the steps there appears to be plaster detachment next to the plaster mesh.

I would have knocked away all the loose material and applied a harder A-bruk that withstands moisture better, then repainted.

 

[Plupp 405730]

A-mortar is usually a base coat, you can plaster with cement mortar but it should be consistent throughout..

B-mortar is our most common plastering mortar for traditional plastering of basement foundations and stairs, etc. B-mortar is the lowest approved quality for ground contact..

C-mortar is not suitable for ground contact or cold constructions in our climate as it is too absorbent. Mostly used indoors..

You always have the hardest mortars against the substrate and then plaster with different sacrificial layers on top..

Applying an A-mortar on top of a B-mortar is wrong and will lead to it detaching and cracking..

The most important thing is not to use dense paints; finishing is preferably done with silicate paints or colored surface plasters that are not organic..

Organic Thin Plaster​

Plastic paint, mixed with sand, applied in a thin layer.

 

[neo11]

A little plastering know-how:

A-bruk is usually a foundation mortar, you can plaster with cement mortar but then it should be continuous...

B-bruk is our most common plastering mortar when it comes to traditional plastering of basement foundations and stairs, etc. B-bruk is the lowest approved quality against the ground...

C-bruk is not suitable against the ground or cold constructions in our climate as it is too absorbent. It is most often used indoors...

You always have the hardest mortars against the substrate and then plaster with various sacrificial layers on top...

Applying an A-bruk on top of a B-bruk is wrong and will lead to it coming loose and cracking...

Then the most important thing is not to use dense paints, coloring should preferably be done with silicate paints or colored surface plasters that are not organic...

Organic thin plaster​

Plastic paint, mixed with sand, applied in a thin layer.

Do not understand the post.
We are suggesting A-bruk since B-bruk cannot handle these conditions.

 

[Plupp 405730]

Don't understand the post.
We are suggesting A bruk since B bruk cannot handle these conditions.

Then maybe you haven't read all the posts😉

 

[neo11]

Sure, but then maybe you should have quoted that post then.
Personally, I don't need any putslära 😉.

 

[Plupp 405730]

Sure, but then maybe you should have quoted that post.
Personally, I don't need any trivial knowledge 😉.

I didn't want to be so direct and instead presented general knowledge that doesn't harm anyone and can be useful for many to know...
Most on BH are not professional craftsmen...
If you're a mason, I understand you have those skills, otherwise that would be bad😉

 

[neo11]

Have been a bricklayer for over 25 years

 

[Plupp 405730]

Have been a mason for over 25 years

Yes, what do you want with that?

The post at the beginning was not directed at you..