Terrace on flat roof - structure - covering

At my apartment, there is also a rooftop terrace on the garage. There are 40x40x 3-4 cm colored concrete slabs (sand yellow) laid on height-adjustable [Plattenlager].
Google search: height-adjustable [Plattenlager]

I have not checked whether it is possible to work with 5 cm here. For me, it was between 8 and 14 cm. The advantage is that you can really level the terrace well, and water runs off very well under the slabs toward the roof drain.

For the concrete slabs, I chose a color tone that is very close to that of my tiles in the living room. When you look out from the terrace door now, it always looks like a slightly extended living area and there is no harsh color contrast.

There are plate bearings for this low installation height, but you should then choose a sufficiently large plate with a thickness of 3-4 cm, otherwise stability is not guaranteed. In my opinion, at least 40 x 80, as they have enough own weight. However, with this roof structure, an additional layer should still be planned for the protection of the [Dachhaut].

By the way, is a fall protection planned for this terrace construction?

The 40x40 ones hold quite well for me. The support plates are relatively large. With 40x80, I could imagine that height adjustment becomes more complex because with 80 cm, quite a bit of slope is overcome. And that it tends to be more wobbly especially then.

Phew, that's good then, construction expert!

Thanks for your info, KTB. I've heard about that too. However, I've also heard that these pedestal supports can slip if you have a "soft" substrate like we do. The insulation actually gives a bit when walking on it. Have you noticed anything like that?

We have a masonry parapet as fall protection. I think it's great since it also serves as privacy from the street.

What do you think about the "splitting bed"? It currently seems the cheapest and simplest option to us. You can especially do it yourself.

So, I don’t notice any slipping, etc. And, I also have a brick parapet. So nothing can really slip there either. Unfortunately, I don’t currently remember what is directly under the stilts. I need to try to ask my landlord about that.

For a gravel bed, the installation height is too low. A gravel bed should ideally be 4-5 cm thick, at least 3 cm. However, you should not even consider placing the 2 cm thick ceramic tiles directly on the gravel. That would make the setup even more unstable than using pedestal supports. The ceramic tiles do not have enough own weight and the gravel layer is too thin to absorb forces coming from above. Additionally, a drainage mat about 2 cm thick should be laid under the gravel, otherwise the tiles will start to float during heavy rain. For an area of about 40 m², a solution with wood could be possible. Why not divide the area and build a corner platform?