ᐅ Patio: Laying Tiles on Crushed Stone Base

Dear Ladies and Gentlemen,
Dear forum members,

The house construction is progressing, and I now need to start thinking about the terrace.
It will be a corner terrace (south-west facing) of about 90 sqm (970 sq ft).
The house description (scope of work) includes a gravel base with Jura gravel that ends approximately 20 cm (8 inches) below the finished terrace height, providing the option to add crushed stone or similar material.
I would like to install 90 x 90 cm (35 x 35 inches) R11 tiles with a thickness of 2 cm (0.8 inches).
Is it possible to lay them on crushed stone, and do I need so-called spacers or pedestals?
Thank you very much.

You can do that without any problems, but make sure to compact the soil properly beforehand.

Good morning Bookstar,
thank you for your feedback.
Is it possible to use a tile measuring 90 x 90 cm (35 x 35 inches) with only 1 cm (0.4 inches) thickness, or does the tile need to have a certain minimum thickness?

Thank you.

In my opinion, gravel is only suitable for height adjustments of 3-5 cm (1-2 inches). If your builder constructs a layer of 20 cm (8 inches), you would still need to add about 12 cm (5 inches) of gravel in between, or have it installed higher right away.

A thickness of 1 cm (0.4 inches) breaks too easily. 2 cm (0.8 inches) is the standard.

I don’t have personal experience yet. However, I was advised to use at least 3 cm (1.2 inches) slabs for installation on gravel. 1 cm (0.4 inches) slabs should be glued.

I have mentioned this elsewhere: our trusted tiler advises against using gravel and recommends pedestal supports instead. This is likely because larger tiles tend to be more prone to deflection.