I have to ask too- what makes the building steampunk?
I'd have to say that what makes a building Steampunk is simply the level of detail. If you can look at it for hours and continually find more interesting details to look at, then it qualifies. This is why, in my opinion, so much "modern" architecture and city planning gives rise to bland, arid, soulless cityscapes. A bare concrete wall is simply - a bare concrete wall. It does nothing to hold anyone's attention. Whereas the level of sheer Baroque detail in a building such as, for example, St. Pancras Station in London, rewards close attention; every detail leads on to further detail, ad infinitum almost.You could spend hours, days probably, just looking at the frontage - let alone the interior.
Athanor.