The plaster is coming off from a one-year-old concrete wall.

[Paxman]

Hello!

Now I have to ask the forum's collective expertise again.

Just over a year ago, we got help from a company to build a small retaining wall when our parking lot was being prepared. The wall was cast in a normal plywood form and then plastered. Now this plaster has begun to come off, and I am a bit curious about why this is happening.

We have, of course, contacted the company that provides a 3-year warranty, and they are supposed to come here and take a look at this (and another matter that is more straightforward).

Can you see from the picture below exactly what the company did wrong? I would like to have a bit of leverage in case there is a discussion about whether they should fix the damages or not, and if they take responsibility (which I think they will), how they should do things differently so that the same issue doesn't happen again.

Can they claim that we did something that caused the plaster to come off?

Best regards,
Fred

 

[Stefan N]

It has probably frozen and broken. No crowning on the wall?

 

[eviljava]

Frost heaving?

Moisture (precipitation) penetrates the horizontal surface and causes frost heaving.

 

[Paxman]

Well, frost splitting seems like the most likely cause. But why has it happened? Shouldn't you be able to render concrete without the moisture getting in and breaking it away when it freezes? The plinth of our house is rendered and it hasn't broken off.

Regarding crowning, I guess it's making the surface convex. This hasn't been done, but the entire wall slopes slightly down towards the end visible in the picture.

 

[eviljava]

The plinth of our house is plastered and it hasn't been blasted off.

The plinth on your house is vertical and maybe even painted/treated? It probably doesn't accumulate as much moisture as this wall?

But frost damage is common on vertical surfaces too, e.g., plaster/brick facades. This can be avoided by painting/hydrophobing the surfaces.

 

[Paxman]

So the risk is that the company will say that since we haven't painted the surface, they won't cover replastering under warranty?

 

[eviljava]

So the risk is that the company says that because we haven't painted the surface, they won't cover the plastering under warranty?

Yes, the risk is that they claim it hasn't been weatherproofed... There's also a chance they'll fix it without complaints. ☺

In my world, this is like hiring a carpenter to build a railing with a cap in untreated wood, ignoring oiling/painting the wood, then complaining when the cap starts to mold/rot.

On the other hand: if you've ordered a wall that stands exposed to the elements, perhaps the craftsman should have constructed it to be "more weather-resistant," one might think? Alternatively, informed you about putting metal on top, treating it, etc.

I am not good with the legal aspects and have no idea what you've agreed with each other?

Now, I don't know how long the wall is, but if it's only a few meters, it's not so expensive to fix, regardless of whether it's you or the company who fixes it.

 

[Paxman]

I completely agree with your reasoning, eviljava, even though I might think that plaster should withstand the elements a bit better than untreated wood. I actually don't remember if the company informed us about the importance of painting the plaster or not.

The thing is, they haven't been 100% in their execution in several other parts of the job, so I mostly wanted the forum's opinion on whether the plaster was obviously done incorrectly. For example, if it's too thin.

If the company claims that we contributed to the plaster coming off, I won't argue with them about it, but will probably fix it myself.