I live in an ex-council semi that was thrown up in the 1930s.  It's always puzzled me as to why the ground floor (originally just made up of living room at the front and kitchen/pantry at the rear) was built with a suspended wooden floor at the front half and a solid concrete floor in the rear half.  There isn't any form of cellar.  The space under the floorboards is too small to climb into.

Was this done for any practical reason, or just for aesthetics?  Originally the wood floor was painted dark brown round the edge with a large square of linoleum in the centre, and thebconcrete had marley floor tiles.  

The only practical reason I've come up with is that it was to deliberately make the room drafty to let the open fire breath properly

Around that time there was a shortage of timber, you may also notice there's not much timber over 8ft and the loft is built with 3x2.