Which flooring is recommended for a balcony?

Looks good.

Thank you very much!

Has this been implemented on a garage?

No, it is on the flat roof of the living room. In my profile picture, you can see it in the foreground.

How are the decking boards fixed?

On the roofing membrane lies a protective mat. Then comes the substructure, laid on terrace pads for level adjustment, followed by the WPC decking boards. Here is another picture from the construction phase.

I now have the first cost estimate from a carpenter (assembly services approx. around the house and garden) for the balcony area of just 5 sqm:

Demolition of existing tiles and screed, new sealing with bitumen welding membrane, new installation of BPC terrace decking: all together incl. VAT about €4,600, with the option that it can become more expensive daily. Is that normal?

Removal of existing tiles and screed, re-sealing with bitumen welding membrane, new installation of BPC terrace decking: all together incl. VAT about €4,600,-- with the option that it may become more expensive daily. Is that normal?

Is that normal? Yes! A small area is always more expensive per sqm. And it is an extensive job with various steps and not quite easy to do correctly. The sealing must, for example, be done properly, which involves a lot of fiddly work on a small area.

Is that with material? Then it would even seem quite good to me...