ᐅ Installation of click-lock wood composite tiles on a rooftop terrace

Hello,

I am a bit unsure about installing these click-together tiles.
I live in a new build and would like to create a path on the flat roof terrace (enclosed) using these "click tiles."
The roof terrace is currently covered with classic round natural stones, about 6–7 cm (2.5–3 inches) in size, with a geotextile fabric underneath.

Can I simply move the stones aside and lay the click tiles directly on the fabric, or should I install an additional base layer on top of the fabric?
So far, people have walked directly on the stones that lie on the fabric, so I assume an extra base might not be necessary. However, since I am not sure, I would appreciate advice from the experts. Thank you very much in advance.

I would be cautious about using wood-based panels outdoors.

The gravel also serves certain purposes; there must be a reason why it was laid on your terrace. Among other things, it reduces the sunlight exposure on your waterproofing.

It is a wood-plastic composite (WPC) that is characterized by slip resistance and UV resistance – ideal for long-term outdoor use – so it should be suitable.

blockholzer schrieb:

It is a wood-plastic composite (WPC) "characterized by slip resistance and UV resistance – ideal for permanent outdoor use" – so it should be suitable.

Unfortunately, this opinion is not entirely accurate! Wood-based materials, especially when exposed to weather outdoors, still have enough potential to cause future frustration and problems.
WPC decking boards, whether solid boards or hollow chamber systems, are only and exclusively designed for ventilated installation on load-bearing joists (substructure).
In addition, the boards must be installed with a slope of 1–1.5%.
A quick and durable alternative would be the installation of "GTI Max tiles" directly on a level fleece layer.
The tiles come in various colors, are made of synthetic rubber, are about 6mm (0.24 inches) thick, and have very durable dovetail edge locking.
A cost comparison with WPC decking is definitely worthwhile; regarding durability, the GTI tiles (from practical experience) would also be my recommendation!
Best regards and good decision: KlaRa

KlaRa schrieb:

Unfortunately, this view is not accurate! There is quite a bit of potential for future frustration and problems, especially with wood-based materials in exposed outdoor areas.
WPC decking boards, whether solid or hollow-core systems, are exclusively designed for ventilated installations on load-bearing joists (substructure).
Additionally, the boards must be installed with a slope of 1–1.5%.
A quick and durable alternative would be to lay "GTI Max tiles" directly on a flat fleece layer.
These tiles come in various colors, are made of synthetic rubber, are approximately 6mm (1/4 inch) thick, and feature very durable dovetail locking edges.
A cost comparison with WPC decking is definitely worthwhile. From a practical standpoint, I would also recommend the GTI tiles for their durability!
Best regards and good luck with your decision, KlaRa

I have now decided to lay foam polystyrene boards over the gravel and place the click tiles on top. A simple and affordable solution that should also provide a certain level of durability... hopefully.

Of course, it is up to each individual how they carry out an extension or finishing work under their responsibility.
Here in this forum, we limit our responses to practical experience that offers the highest level of safety in preventing construction damage (and thus ensuring the success of a trade).
Styrofoam boards on a gravel bed combined with a mechanical locking system for a wood-based panel surface are certainly not among the construction methods that are promising—at least not in the medium term.
So, I wish you much success with the execution of the (quote) "affordable and simple option"!
Regards, KlaRa