Terrace covering - WPC or porcelain stoneware?

@ PhilippK: "Is installation on pedestals optimal for porcelain stoneware? Or rather on drainage concrete? Directly on gravel?" Answer to this: with only 20mm tile or slab thickness (that was your information) they are not self-supporting. This means: 20mm thick tiles cannot be used on pedestals, as they will break under load. For this, slabs about 40mm thick are necessary. You certainly will not install drainage concrete, but rather drainage screed. This is always built on a single-grain basis (so that drainage can occur through the material structure). The disadvantage of this non-standard substrate is obviously the lower flexural tensile and compressive strength due to the single-grain construction, which can only be compensated by considerable additional thickness. So the installation in a gravel bed remains if only a material thickness of 20mm is available! ------------------------- Regards: KlaRa

Hello KlaRa, Sorry, but this is simply not correct. Porcelain stoneware terrace slabs with 2cm thickness can be easily installed on pedestals and will not be hollow. Please do not spread such falsehoods. I would also like to link further details with meaningful contributions from me here but was already snapped at for it this afternoon. Since you are a mod here, it would be nice to get some information on whether this is allowed. Best regards Christian

I have to correct myself regarding my statement about the necessary slab thickness or withdraw it and apologize for that: Christian Glan is right. There are 20mm thick terrace slabs that are advertised for installation on pedestals! @ Christian Glan: One must admit that references to one's own work in a forum that prides itself on passing on professional information from knowledgeable sources to the homeowner bring a certain bitterness to the tip of the tongue. A certain self-interest, at least the almost pressing suspicion that then arises, cannot be completely denied in such a link to the questioner(s). If the admin - and only he is capable of this - "grumbled" at you today (quote), he certainly did not do so without reason. And if you (please see your response text) ask whether this is allowed, I can only answer with reference to the sentence above ["(...) was already grumbled at this afternoon. Since you are a mod here, it would be nice to get some information regarding whether this is allowed."]: Yes, he is allowed to, it is permissible. Regards: KlaRa

We have ceramic tiles 2cm thick with 90x45cm

With us they would be laid directly in gravel, but some sound hollow when walking on them, which annoys me, my wife doesn't even notice.

We made a mistake, you should definitely use tile supports with joint crosses, they are available with a few mm height that lie directly in the gravel, so you can also grout.

And please don't take anthracite, they get very very hot.

While I just got the notification.

In 2020 we actually took up all the tiles and re-laid them. It annoyed me. And now we have about 10cm large gravel bedding supports and no joint sand.

Now it lifts and doesn't sound hollow either.