Bungalow flat roof - reinforced concrete vs wood

But please don’t say bungalow because you save the stairs and flat roof because it would be the simplest :)

Bungalow in Bauhaus style, because we don’t want any problems with age (and therefore climbing stairs) or accidents and wheelchairs, and flat roof because in our opinion it is the most stylish and we are building next to a railway that also has an embankment, so we won’t be too high above the embankment and will thus have fewer noise problems.

In our opinion, reinforced concrete would be safer, since wood naturally moves and expands

But concrete and steel do as well – both materials are used so often because they have the same coefficient of thermal expansion; otherwise, it wouldn’t work.
So a reinforced concrete ceiling is not completely static either!

I would make it dependent on who I am building with. Take what your house builder does best; that’s what he will do best.

I definitely don't see it that way in this case. One can learn from the architectural blunders of the 70s/80s - no wood in flat roofs!

In the end, we decided on a developer with a reinforced concrete roof. We actually have a queasy feeling about a wooden roof. Surely some providers will be able to do it properly without any problems, but the gut feeling has to be right. Thank you for all the contributions.