Possible Clues:

• Building that, in principle, is to house soldiers
• Building for the people, in principle
• People trapped by doctrine in an apartment block
• Holding a belief about humanity
• In principle the chaps provide accommodation
• In principle, people need somewhere to live
• Belief held about folk in flats
• Catfish Row in 'Porgy and Bess,' e.g.
• It's my belief people are trapped in the building
• Accommodation is provided for employees in principle