Ok - a couple of caveats on what I said above - structural engineers do
have to get it right - though their solution may be sub-optimal,
overpriced or ill-considered to the point of chaotic - but it does have
to stay up.

I'd also add that the people that "do" in the building trade have in my
experince a higher degree of competance - the ones that have to "make
it work" tend to be much more down to earth/pragmatic/realistic (and
better value for money) in their solutions and recommendations through
hard-won experience.