Terrace roofing on ceramic tiles on prefabricated house

Frost-free depth at least 80 cm. You can use shuttering blocks for the small roof, they don’t cost much but they are bigger than your 15 by 15 cm. You place them in and fill with concrete, done. Unfortunately, you have to destroy some of your tiles, but that way you are on the safe side.

Why does it have to be self-supporting because of timber frame construction? We also get timber studs and with us the patio roof is attached at the height of the intermediate ceiling, there is always a thick beam there anyway, it doesn't get any easier.

You should still clarify it with the house building company, because only they know whether it works just like that or not.
If I do it like that with our carport, then I have serious problems with my house.
It depends on what you want to attach to the house.

I have to get back in touch again, as it is now entering the critical phase and I am having problems with my foundation. I just can't go down to 80cm. From 50cm down there is clay soil and I can't get through it. I can scrape off a layer by tenths of a millimeter, but that's it. Even with a large drill and hammer, I can't get through it. Does it have to be frost-free founded for normal post supports?

I just can't get down to 80cm. From 50cm down there's clay soil and I can't get through. I can scrape off a layer millimeter by millimeter, but that's it. Even with a big drill and hammer I can't get through. Does it have to be frost-proof foundation for normal post brackets?

Yes, it has to be deep. Use a chipping hammer drill (Hilti caliber) to go into the soil and loosen it.

Tip: A manual earth auger (like from MWS Apel) or planting auger also works wonders and costs little. I took the large 300mm version and it cuts like a hot knife through butter... The 70 cm standard handle is enough, the handle extension to 100 cm makes it unwieldy (you bump into your own legs) and doesn't add that much leverage.

Also had clay and then found a device called GardenClaw in the basement for the foundations. That worked quite well.