ᐅ Pedestal supports for patio slabs directly on frost protection layer?

Hello!

We have added about 40-50cm (16-20 inches) of frost protection material for our terrace. Now I am considering the installation. Can adjustable pedestal supports be placed directly on the compacted frost protection layer? Maybe with a weed barrier fabric in between? The plan is to use 60x60cm (24x24 inches) porcelain tiles.

I would like the terrace to be flat without any slope because there is a cold winter garden on the terrace, and due to the sliding doors, it cannot have any slope. This means there would be a height difference sloping away from the house. A 2% slope over 4 meters (13 feet) means about 8cm (3 inches) difference. With pedestal supports, water can run into the joints and drain through the substructure.

What I also like about this construction is that individual tiles can be lifted later and the height can be adjusted if the subbase settles a little.

You should place slabs under the pedestal supports.
For this, you can also use simple edge concrete blocks (2.50 euros at the hardware store).
Only place them spot-wise under the pedestal supports, not over the entire area.
Make sure to lay a weed control fabric underneath; the fabric sheets should overlap properly.

And why put boards underneath? Nothing should happen with compacted material, right?

I have already asked specialist companies here, but they seem to have little to no experience with pedestal supports.

Because the gravel you have on top settles a bit, the terrace might shift slightly. However, if you want it to look good for a long time, you can take measures to prevent this.

Once my canopy is finally in place, I will start working on my floor.
I'll gladly share pictures with you, if I don't forget.