Polypropylene cladding as used in food factories?
That can be steam cleaned without difficulty.

Copying "Lloyds building" for all services on the
outside, requires a huge amount more land tho.
Allows the "entire building to be steam cleaned",
removes ceiling tiles & assocated services etc.

Many do not look particularly well designed, I
think we have only just managed to avoid the
"airborne sneeze in one ward ends up next door".
--
DB.