I would imagine the structural engineer will say no, probably mainly to cover himself if something were to happen!
A lot of European and Asian fishkeepers live in flats and have large fishtanks without problems and I've seen a fair few larger tanks in flats in the UK in my time too. The weight on the floor/joists is a sheer weight so it won't be moving about, once it's there it's not going to be wobbling or changing stresses on the floor.
I wasn't trying to be an ass about it all, it's just you're stuck in a crappy situation that the only real way to find out about is to do it. You'll hear a million different opinions on it from various people but just remember opinions are like ********s, everyone has one.
Until either a structural engineer nixes the idea or you go ahead with it, this thread won't progress and you'll just build up more and more confusing information.
Good luck with it and I'll keep my fingers crossed for you!
Sorry my bad, I took it the wrong way.
See that's the problem I'm facing - go for it and hope for the best or second option (probably safer) is get someone to look at it first.
If it is safe then why would he say no I cannot have it? It's his job to tell me whether or not its okay or not.
I've read around and seen obviously every floor is different and every floor concrete or wood has a limit you have to work out either by yourself or get someone to do it since just because one person has successfully got a large tank upstairs does not mean another can.
I'm presuming the old school lot on this forum has seen this question asked so many times, my apologises. It's a very controversial and complex question too.
It may be a sheer weight but its going to way so much that it if it goes wrong then I will be in deep trouble...
Such a horrible situation.