Experience with 3cm thick terrace slabs - do they break?

don't the edges burst if they lie without a gap?

No. Nothing is burst or broken/chipped. But these are also higher-quality slabs from a natural stone specialist retailer… although open-pored :rolleyes:

Just a question: what exactly is meant by mortar bed including drainage? What is the exact structure of such a mortar bed?

Thanks!

Simply take split or sand with a grain size of 1-3mm and mix with cement.

We have now had several landscape gardeners here and will have these thin slabs glued down, so hopefully nothing will sink and nothing will break. On our west side, we have 2 windows each 3m wide (sliding lift door). The west is our weather-exposed side and we will have the terrace laid out across the entire width of 12m. One landscape gardener insisted on installing a drainage channel along the house wall to keep moisture away from the masonry. The normal slope of the terrace would not be sufficient for larger rainfalls. With the channel, the rainwater would immediately seep away and could not cause any damage to the foundation. We then asked all the other landscape gardeners about this and none of them have ever installed drainage in a terrace. What do you think? How have you solved this? Is drainage directly at the house necessary on the terrace?

You only really need drainage directly in front of doors. The masonry must in any case be sealed up to 30cm above ground level, but you should take into account the [Geländeoberkante] discussed back then. If all of this is done properly, it doesn't matter much if water stands briefly on the wall during 2 thunderstorms a year.