ᐅ Newly installed patio with concrete paving slabs – is this normal?

Hi!

Our builder has finally started work on the terrace. Completion is imminent.

Now, with the middle slabs, the following situation has appeared (see photos).

According to the installer, this can happen occasionally... it is a chemical reaction and the appearance issue should fade after a few months. Unfortunately, I don’t have any knowledge about this.

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

The stain in the close-up photo was treated by me with water and a sponge – but it didn’t help.

I would appreciate a prompt response.

Good luck & thanks!

There is lime leaching out of the concrete, causing these stains on our exposed concrete stone wall. Unfortunately, this has been going on for about a year now and it’s not getting any better 🙁 If anyone has tips on how to remove it, please share.

Nothing will fade... it’s already bright where you are anyway

These are efflorescence deposits caused by excess lime, in my opinion. Can it be scrubbed off with a brush? Otherwise, rain will take care of it over the next few years. It may even get worse for a while at first. You can impregnate or seal concrete to prevent this from happening. Alternatively, you can order a high-quality mix at the plant to reduce the lime surplus problem. For exposed concrete, I would definitely order sealing or impregnation directly from the factory to avoid any issues. For patio slabs from the builder, however, this is more wishful thinking.

Good morning,

thank you for the initial quick responses.

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

@Alex85
As you already mentioned, sealed/impregnated concrete slabs from the builder are quite unlikely.

But is this allowed? The terrace was just recently installed. For now, I want to know if this has to be accepted as something that can happen – or if it is clearly unacceptable and the slabs should not look like this when newly installed.

Good luck

Gatho schrieb:
Good morning,

thanks for the initial quick responses.

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

@Alex85
As you already mentioned, sealed/impregnated concrete slabs from the builder are quite unrealistic.


But is this acceptable? The terrace was just freshly installed. My main concern is whether this needs to be accepted because it can happen – or if it is clearly not acceptable and the slabs should not look like this when newly laid.

Good luck

What can the terrace installer do about it? You chose the stones and their quality yourselves, right? The installer doesn’t have to do anything. Maybe he could have warned you that this might happen since as the client you can’t know everything. It can happen. I have seen and read about this many times.

In our case, it will probably look similar. We are planning a dark stone for the driveway, like Alex. The terrace will be tiled so that something like this doesn’t happen.