Use a carport as a patio cover?

The panels recommended in post 10 do not need additional support at 3 m width. 16 mm is anyway the minimum for roof terraces. The example you described for greenhouses is not representative, much thinner panels are used there. Of course, the panels must be installed properly. There are online construction instructions. But I am not allowed to link them here.

I did not mean your post directly, but rather in general that the OP is probably looking for the most cost-effective solution and might consider using somewhat thinner and simpler materials here and there...... Of course, that also works just as well with these panels; there are many suppliers who basically execute this with multi-wall panels. Still, I don't really like it that much.