Complex sentence: Finally in 1984 the board developed the former stables into a history classroom while an upper floor house for a house master and his wife; these have all now been turned into living areas today.
Split into simpler sentences: Finally in 1984 the board developed the former stables into a history classroom while also creating upper floor house above, for a house master and his wife to reside within. These have all now been turned into living areas today.