Foundation for posts terrace roofing

We did not cut out the slabs, but had them drilled. Nothing broke with us, but our terrace slabs are also 8cm thick.

With 8cm slabs, I would also have less concern there.

Aren't they always inward-facing? At least with us, you can't see anything there.

Externally mounted dowels are easier from a construction and assembly perspective because they are more accessible. Therefore, I would at least not categorically exclude that. It is quite possible that there are manufacturers who pay attention to this and fasten them inward-facing.

I also think that I’ll first build the foundations and then screw the posts of the canopy on. Then I’ll cut out the panels and lay them around. That should work out. With an angle grinder and the right blade, that should be doable.

The question is what to use as a foundation. Ultimately, a 40mm pipe makes sense that I just put into the ground (maybe with some kind of aluminum profile underneath so that everything is straight, and then fill this pipe with concrete, right?

The canopy weighs about 550kg. It gets 2 posts and is attached to the wall by the terrace. In the end, there are actually hardly any forces acting here – especially with the "light" canopy.

For me, I think it’s more important to dig deep enough!

One more question: If I place the post directly on the concrete foundation at the bottom, I will have quite a steep slope since my slabs are 5cm thick and the cut slabs still need to be set into the gravel bed so that everything sits level. Therefore, the foundation should be 5cm deeper than the top edge of the terrace slabs.

Is this basically "standard" and does it ultimately give me the slope I need, or is there something else I need to consider? If I drill through the slabs, I will be sitting much higher and would ultimately have to position the wall mounting higher, correct?

Measured everything over the weekend and marked the post.

I believe the problems are obvious... The construction of the foundation will actually be somewhat more complex than expected