ᐅ Pergola Awning Post Installation on Paving Slabs

Hello everyone,
We would like to replace our awning located on the roof terrace. It faces west.
We have received an offer (just under 19,000 CHF) for a pergola awning combined with a vertical awning.
The installer plans to secure it using flower boxes measuring 50x50x50 cm (20x20x20 inches), each weighing 150 kg (330 lbs). Two of these are required.
However, they take up a lot of space.

Questions:
We have come across the Sowol pergola awning.
The posts are mounted using floor flanges.
Is it possible to install the posts on the paving slabs? These are laid on gravel. There are also flower boxes standing on the paving slabs, see photo.
The awning will still be fixed during installation.
We would prefer not to drill into the roof to attach the mounting flanges.

Thank you very much for your help.

Best regards,
Sandro

We are currently facing the same issue (although not with a roof terrace). I was already aware that attaching directly to the terrace slabs is not possible. However, I hoped that the edge stones, which actually have a solid foundation, could be used. I had planned to use a metal bracket that could be slipped over the edge stones. However, two different awning installers corrected me on this. Unfortunately, there is no way around having a proper foundation. Therefore, I think the suggestion with the two flower boxes will be the only solution for you.

The existing awning looks quite high quality. Why does it need to be removed? Would re-covering it not help?