Newly laid terrace with concrete stone slabs -> is that normal?

Hi!

Our developer has finally started with the terrace. Completion is imminent.

Now, the following picture appears on the middle slabs (see photos).

According to the installer, this can happen sometimes... it is a chemical reaction and the problem with the appearance would fade after a few months. Unfortunately, I have no knowledge about this.

What is your assessment? Is this normal? Will it go away or is it a clear defect and the slabs need to be replaced?

I tried to remove the stain from the close-up photo with water and a sponge - but it did not help.

I would be very happy about a prompt response.

Best regards & thanks!

In the concrete, lime is washing out, we have these stains on our exposed concrete stone wall. Unfortunately, it has been like this for 1 year now and it is not getting better :( if anyone has tips on how to get rid of it, please share.

If nothing fades... it is already bright with you

These are efflorescences caused by excess lime in my opinion. Can it be scrubbed off with a brush? Otherwise, the rain will take care of it over the next few years. It may also get worse for a long time initially. Concrete can be impregnated or sealed to prevent this from happening. Or commission a correspondingly high-quality mix at the plant so that excess lime is less problematic. For exposed concrete, I would directly order sealing/impregnation from the factory so that nothing happens. For terrace slabs from the developer, however, this is rather wishful thinking.

Good morning,

thank you for the first quick feedback.

In one of the photos you can already see the wet spot - there I tried to remove the excess lime with a brush and water, but without success. The slab looks unchanged.


As you already said, sealed/impregnated concrete slabs from the builder are pretty unrealistic.

But is that allowed? The terrace was just freshly laid. For now, I want to know whether you have to accept it because it can happen - or if it is clear that the slabs should not look like that when newly laid.

Best regards

Good morning,

thanks for the first quick feedback.

In the one photo you can already see the wet spot – there I tried to remove the excess lime with a brush and water, but without success. The slab looks unchanged.


As you already said, sealed/impregnated concrete slabs from the builder are quite unrealistic.


But is that allowed? The terrace was just freshly laid. For me, it’s first about whether you have to accept this because it can happen – or whether it’s clear that the slabs, if newly laid, are not supposed to look like this.

Best regards

What can the terrace builder do about that? You guys chose the stones including the quality, didn’t you? The terrace builder doesn’t have to do anything. Maybe he could have told you that something like this can happen, since as a client you’re not all-knowing either. It can happen. I’ve seen it several times and read about it here.

It will probably look like that for us too. And we are planning a dark stone for the driveway, like Alex. The terrace will be tiled so that something like this doesn’t happen.