On 12/03/2018 12:19, John Rumm wrote:
Personally I fitted a 210L one which is probably about 5' tall.

If I replaced my bog standard tank with one of those, bearing
in mind the appalling way the 1st floor joists were attached with
joist hangers (4 or 5, 4 inch round nails half in and then bashed over),
it might end up in the lounge.

There is already 20mm ceiling deflection where the tank is !!