Is a terrace with natural stone slabs on a concrete foundation possible?

Hello everyone,

we would like to have a terrace with natural stone slabs and currently have the following construction (13 years old):

[*]Compacted recycling
[*]Concrete slab 18 cm
[*]Slope screed (only 1% incline!) with reinforcement and waterproof membrane under the screed
[*]Porcelain stoneware glued
[*]Aluminum profiles on the edges

The aluminum profiles are now loose and some edge tiles are also loose and/or broken.

We now want a terrace with natural stone slabs and have the following idea:

[*]Remove porcelain stoneware tiles
[*]Grind slope screed to 2-3% incline
[*]Lay studded membrane (studs facing up, overlapping strips, like roof shingles)
[*]>= 3cm basalt premium gravel on top and level to 2% incline
[*]Lay slabs unbound on gravel
[*]Set edge stones

Now our questions:

[*]Is it possible to lay natural stone slabs on gravel on a concrete slab this way? If not, how else would it be possible?
[*]Should/must one use a drainage fleece? If yes, directly on the studded membrane or directly under the slabs?
[*]Generally about laying on gravel: Can it remain permanently damp under the slabs due to remaining drops (even with a slope) and would that be a problem?

Thanks in advance for any answers!

P.S.: The total construction height is not a problem for us

Hi,
it works without drainage fleece. What is important is a layer of gravel with at least 6 cm. And very important: use gravel size 5-8.
Otherwise, you will get those famous damp spots in the natural stone. If unknown, quickly google it afterwards.
Most people use gravel 2/5 or 0/5, but these are not! capillary-breaking. With concrete slabs, that is no problem, but with natural stone, you then get the damp spots.

Or just prop up.

Thank you for your hints!

I think I will do it with 5/8 split on a Dörken Delta MS dimpled membrane with slope. It can handle a lot of force/weight and is durable.